JP2021017481A - Ink composition and method for producing the same, photoconversion layer, and color filter - Google Patents

Abstract

To provide an ink composition that can reduce a wavelength shift of conversion light in a pixel unit.SOLUTION: An ink composition has light-emitting nanocrystal particles, a photopolymerizable compound and/or a thermosetting resin, and a zinc compound having two ligands. The two ligands each have a sulfur atom, and the sulfur atom is directly bonded to a zinc atom, resulting in coordination to the zinc atom.SELECTED DRAWING: None

Description

The present invention relates to an ink composition, a method for producing the same, an optical conversion layer, and a color filter.

Conventionally, a pixel portion (color filter pixel portion) in a display such as a liquid crystal display device is a curable resist containing, for example, red organic pigment particles or green organic pigment particles and an alkali-soluble resin and / or an acrylic monomer. It has been manufactured by photolithography using materials.

In recent years, there has been a strong demand for lower power consumption of displays, and instead of the red organic pigment particles or green organic pigment particles, luminescent nanocrystal particles such as quantum dots, quantum rods, and other inorganic phosphor particles have been demanded. Is being actively studied for methods of forming pixel portions such as red particles and green particles.

By the way, the method for manufacturing a color filter by the above photolithography method has a drawback that a resist material other than a pixel portion including relatively expensive luminescent nanocrystal particles is wasted due to the characteristics of the manufacturing method. Under such circumstances, in order to eliminate the waste of the resist material as described above, it has begun to be studied to form a light conversion substrate pixel portion by using a curable ink composition by an inkjet method (injection method). (Patent Document 1).

International Publication No. 2008/001693

The light incident on the color filter pixel portion (hereinafter, also simply referred to as “pixel portion”) containing the luminescent nanocrystal particles is absorbed by the luminescent nanocrystal particles and then has an emission wavelength peculiar to the luminescent nanocrystal particles. It is converted into the light of the above and emitted from the pixel portion as the converted light. At this time, the wavelength of the converted light emitted from the pixel portion may shift to a longer wavelength side than the emission wavelength of the luminescent nanocrystal particles. If such a wavelength shift can be reduced, further expansion of the color gamut is expected.

Therefore, one of the objects of the present invention is to provide an ink composition capable of reducing the wavelength shift of the converted light in the pixel portion.

One aspect of the present invention contains luminescent nanocrystalline particles, a photopolymerizable compound and / or a thermosetting resin, and a zinc compound having two ligands, each of which has two ligands. The present invention relates to an ink composition having a sulfur atom and coordinating with the zinc atom by directly bonding the sulfur atom to the zinc atom.

According to the ink composition on the above side surface, it is possible to reduce the wavelength shift of the converted light in the pixel portion.

The molecular weight of the zinc compound may be 700 or less.

The two ligands of the zinc compound may be compounds having a dithiocarbamic acid group as a coordinating functional group.

[式（Ｉ）中、Ｒ^１及びＲ^２は、それぞれ独立して、水素原子又は炭素数１〜１０の炭化水素基を示し、複数のＲ^１は互いに同一であっても異なっていてもよく、複数のＲ^２は互いに同一であっても異なっていてもよい。] The zinc compound may be a compound represented by the following formula (I).

[In formula (I), R ¹ and R ² each independently represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and a plurality of R ^1s may be the same or different from each other. , A plurality of R ^2s may be the same as or different from each other. ]

The ink composition preferably contains a photopolymerizable compound.

The photopolymerizable compound may contain an N-vinyl compound. The N-vinyl compound may be N-vinyl-ε-caprolactam and / or N-vinylpyrrolidone.

When the ink composition further contains an N-vinyl compound, the zinc compound may have a solubility of 1% by mass or more with respect to the N-vinyl compound.

The ink composition may further contain light scattering particles. In this case, the ink composition may further contain a polymer dispersant.

The ink composition can be used to form a light conversion layer. That is, the ink composition may be an ink composition for forming a light conversion layer.

The ink composition can be used in an inkjet manner. That is, the ink composition may be an inkjet ink.

Another aspect of the present invention comprises the step of mixing luminescent nanocrystal particles, a photopolymerizable compound and / or a thermosetting resin, and a zinc compound having two ligands. The method for producing an ink composition, wherein each of the two ligands has a sulfur atom, and the sulfur atom is directly bonded to the zinc atom to coordinate with the zinc atom. Regarding.

According to the manufacturing method of the above aspect, an ink composition capable of reducing the wavelength shift of the converted light in the pixel portion can be obtained.

Another aspect of the present invention includes a plurality of pixel portions and a light-shielding portion provided between the plurality of pixel portions, and the plurality of pixel portions are luminescent including a cured product of the ink composition described above. The present invention relates to an optical conversion layer having a pixel portion.

The light conversion layer contains, as a light emitting pixel portion, light emitting nanocrystal particles that absorb light having a wavelength in the range of 420 to 480 nm and emit light having a light emitting peak wavelength in the range of 605 to 665 nm. A sex pixel portion and a second luminescent pixel portion containing luminescent nanocrystal particles that absorb light having a wavelength in the range of 420 to 480 nm and emit light having an emission peak wavelength in the range of 500 to 560 nm. You may be prepared.

The light conversion layer may further include a non-light emitting pixel portion containing light scattering particles.

Another aspect of the present invention relates to a color filter including the above-mentioned optical conversion layer.

According to the present invention, an ink composition capable of reducing the wavelength shift of conversion light in a pixel portion, a method for producing the ink composition, and an optical conversion layer and a color filter using the ink composition are provided. Can be done.

FIG. 1 is a schematic cross-sectional view of a color filter according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail. In the present specification, the numerical range indicated by using "~" indicates a range including the numerical values before and after "~" as the minimum value and the maximum value, respectively. Further, in the present specification, the "cured product of an ink composition" is obtained by curing a curable component in an ink composition (in the case where the ink composition contains a solvent component, the ink composition after drying). Is to be done. The cured product of the dried ink composition does not have to contain an organic solvent.

<Ink composition>
The ink composition of one embodiment is a luminescent nanocrystalline particle, a photopolymerizable compound and / or a thermosetting resin, and a zinc compound having two ligands, each of which has two ligands. It contains a zinc compound (hereinafter, also simply referred to as “zinc compound”) which has a sulfur atom and is coordinated to the zinc atom by directly bonding the sulfur atom to the zinc atom.

The ink composition is, for example, an ink composition for forming a light conversion layer (for example, for forming a color filter pixel portion) used for forming a pixel portion of a light conversion layer included in a color filter or the like. According to the ink composition, the wavelength shift of the converted light in the pixel portion can be reduced.

The reason why the above-mentioned effects can be obtained by the above-mentioned ink composition is not clear, but the present inventors speculate as follows. That is, the peak of the emission spectrum from the luminescent nanocrystal has a width of about several tens of nm in half width. This indicates that the energy of photons when excited electrons and holes recombine and emit light has a certain width. If the energy levels of excited electrons are widely distributed from high to low, the emission spectrum becomes broad. On the other hand, when there are few excited electrons with low energy levels, the emission spectrum is shortened. Due to its characteristic structure, the zinc compound of the present embodiment acts on the luminescent nanocrystal particles to reduce the low energy level component of the energy levels of excited electrons, or the energy level of holes. It is thought that the high-energy levels of the ranks can be reduced. Therefore, according to the ink composition of the present embodiment, it is considered that the long wavelength emission can be reduced (the short wavelength emission is increased), and as a result, the wavelength shift of the converted light can be reduced.

Further, according to the ink composition, there is a tendency to obtain a pixel portion having excellent external quantum efficiency. Further, according to the above ink composition, excellent ejection stability can be easily obtained in the inkjet method. That is, the ink composition can be suitably used for the inkjet method.

By the way, since the pixel part is used in an environment exposed to light, it is required that the external quantum efficiency is not lowered by light (light stability), but a conventional ink composition containing luminescent nanocrystal particles is used. If this is the case, it cannot always be said that a pixel portion having sufficient optical stability can be obtained. On the other hand, according to the ink composition, the decrease in external quantum efficiency due to the light tends to be suppressed. That is, according to the ink composition, it is easy to form a pixel portion having excellent light stability.

The ink composition of one embodiment can be applied as an ink used in a known and commonly used method for producing a color filter, but without wasting materials such as luminescent nanocrystal particles and a solvent, which are relatively expensive. In terms of being able to form a pixel portion (optical conversion layer) only by using a necessary amount in a necessary place, it is preferable to appropriately prepare and use it so as to be more suitable for an inkjet method than for a photolithography method.

In addition to luminescent nanocrystal particles, photopolymerizable compounds and / or thermosetting resins and zinc compounds, the ink composition contains other components such as organic ligands, light scattering particles, polymer dispersants and organic solvents. It can be further contained. Hereinafter, the ink composition of one embodiment will be described by taking an ink composition for a color filter (inkprint ink for a color filter) used in the inkjet method as an example.

[Luminous nanocrystal particles]
Luminescent nanocrystal particles are nano-sized crystals that absorb excitation light and emit fluorescence or phosphorescence, and for example, the maximum particle size measured by a transmission electron microscope or a scanning electron microscope is 100 nm or less. It is a crystal.

The luminescent nanocrystal particles can emit light (fluorescence or phosphorescence) having a wavelength different from the absorbed wavelength, for example, by absorbing light having a predetermined wavelength. The luminescent nanocrystal particles may be red luminescent nanocrystal particles (red luminescent nanocrystal particles) that emit light having an emission peak wavelength in the range of 605 to 665 nm (red light), and may be 500 to 560 nm. It may be green-emitting nanocrystal particles (green-emitting nanocrystal particles) that emit light having an emission peak wavelength in the range (green light), and light having an emission peak wavelength in the range of 420 to 480 nm (blue light). ) May be emitted by blue-emitting nanocrystal particles (blue-emitting nanocrystal particles). In the present embodiment, it is preferable that the ink composition contains at least one of these luminescent nanocrystal particles. The light absorbed by the luminescent nanocrystal particles is, for example, light having a wavelength in the range of 400 nm or more and less than 500 nm (particularly, light having a wavelength in the range of 420 to 480 nm) (blue light) or light in the range of 200 nm to 400 nm. It may be light of the wavelength of (ultraviolet light). The emission peak wavelength of the luminescent nanocrystal particles can be confirmed, for example, in the fluorescence spectrum or the phosphorescence spectrum measured by using a spectrofluorometer.

The red-emitting nanocrystal particles are 665 nm or less, 663 nm or less, 660 nm or less, 658 nm or less, 655 nm or less, 653 nm or less, 651 nm or less, 650 nm or less, 647 nm or less, 645 nm or less, 643 nm or less, 640 nm or less, 637 nm or less, 635 nm or less. It is preferable to have an emission peak wavelength of 632 nm or less or 630 nm or less, and it is preferable to have an emission peak wavelength of 628 nm or more, 625 nm or more, 623 nm or more, 620 nm or more, 615 nm or more, 610 nm or more, 607 nm or more or 605 nm or more. These upper and lower limit values can be arbitrarily combined. In the same description below, the upper limit value and the lower limit value described individually can be arbitrarily combined.

Green luminescent nanocrystal particles have emission peak wavelengths of 560 nm or less, 557 nm or less, 555 nm or less, 550 nm or less, 547 nm or less, 545 nm or less, 543 nm or less, 540 nm or less, 537 nm or less, 535 nm or less, 532 nm or less, or 530 nm or less. It is preferable to have an emission peak wavelength at 528 nm or more, 525 nm or more, 523 nm or more, 520 nm or more, 515 nm or more, 510 nm or more, 507 nm or more, 505 nm or more, 503 nm or more, or 500 nm or more.

Blue luminescent nanocrystal particles have emission peak wavelengths of 480 nm or less, 477 nm or less, 475 nm or less, 470 nm or less, 467 nm or less, 465 nm or less, 463 nm or less, 460 nm or less, 457 nm or less, 455 nm or less, 452 nm or less, or 450 nm or less. It is preferable to have an emission peak wavelength at 450 nm or more, 445 nm or more, 440 nm or more, 435 nm or more, 430 nm or more, 428 nm or more, 425 nm or more, 422 nm or more, or 420 nm or more.

The wavelength of light (emission color) emitted by luminescent nanocrystal particles depends on the size (for example, particle size) of the luminescent nanocrystal particles according to the solution of the Schrodinger wave equation of the well-type potential model, but the luminescent nanocrystal particles It also depends on the energy gap of the crystal particles. Therefore, the emission color can be selected by changing the constituent material and size of the luminescent nanocrystal particles to be used.

The luminescent nanocrystal particles may be luminescent nanocrystal particles (luminescent semiconductor nanocrystal particles) containing a semiconductor material. Examples of the luminescent semiconductor nanocrystal particles include quantum dots and quantum rods. Among these, quantum dots are preferable from the viewpoints that the emission spectrum can be easily controlled, reliability can be ensured, production cost can be reduced, and mass productivity can be improved.

The luminescent semiconductor nanocrystal particles may consist only of a core containing the first semiconductor material, and include a core containing the first semiconductor material and a second semiconductor material different from the first semiconductor material, as described above. It may have a shell that covers at least a portion of the core. In other words, the structure of the luminescent semiconductor nanocrystal particles may be a structure consisting of only a core (core structure) or a structure consisting of a core and a shell (core / shell structure). Further, the luminescent semiconductor nanocrystal particles include, in addition to the shell containing the second semiconductor material (first shell), a third semiconductor material different from the first and second semiconductor materials, and the above-mentioned core. It may further have a shell (second shell) that covers at least a part. In other words, the structure of the luminescent semiconductor nanocrystal particles may be a structure (core / shell / shell structure) including a core, a first shell, and a second shell. Each of the core and the shell may be a mixed crystal containing two or more kinds of semiconductor materials (for example, CdSe + CdS, CIS + ZnS, etc.).

The luminescent nanocrystal particles are selected as the semiconductor material from the group consisting of II-VI group semiconductors, III-V group semiconductors, I-III-VI group semiconductors, IV group semiconductors and I-II-IV-VI group semiconductors. It is preferable to contain at least one semiconductor material.

Specific semiconductor materials include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSte, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, ZnSe, HgSe, and HgSe. CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, CdHgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSeTe, CdHgSeTe, AlHgSe, HgZnSe, CdHgSe, HgZne InP, InAs, InSb, COLP, PLGAs, PLACSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlNAs, GaAlNSb, GaAlNAs GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb; SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSeS, SnSeTe, SnSe, PbSe, SnSe, PbSe SnPbSTe; Si, Ge, SiC, SiGe, AgInSe ₂ , CuGaSe ₂ , CuInS ₂ , CuGaS ₂ , CuInSe ₂ , AgInS ₂ , AgGaSe ₂ , AgGaS ₂ , C, Si and Ge. From the viewpoint that the emission spectrum of luminescent semiconductor nanocrystal particles can be easily controlled, reliability can be ensured, production cost can be reduced, and mass productivity can be improved, CdS, CdSe, CdTe, ZnS, _{ZnSe, ZnTe, ZnO, HgS,} HgSe, HgTe, InP, InAs, InSb, GaP, GaAs, GaSb, AgInS 2, AgInSe 2, AgInTe 2, AgGaS 2, AgGaSe 2, AgGaTe 2, CuInS 2, CuInSe 2, CuInTe 2 , CuGaS ₂ , CuGaSe ₂ , CuGaTe ₂ , Si, C, Ge and Cu ₂ ZnSnS ₄ preferably comprises at least one selected from the group.

Examples of the red-emitting semiconductor nanocrystal particles include CdSe nanocrystal particles and nanocrystal particles having a core / shell structure, wherein the shell portion is CdS and the inner core portion is CdSe. Nanocrystal particles having a particle, core / shell structure, the shell portion of which is CdS and the inner core portion of ZnSe, nanocrystal particles of mixed crystals of CdSe and ZnS, and nano of InP. Crystal particles, nanocrystal particles having a core / shell structure, nanocrystal particles having a shell portion of ZnS and an inner core portion of InP, and nanocrystal particles having a core / shell structure. The shell part is a mixed crystal of ZnS and ZnSe and the inner core part is InP nanocrystal particles, a mixed crystal nanocrystal particle of CdSe and CdS, a mixed crystal nanocrystal particle of ZnSe and CdS, a core. Nanocrystal particles with a / shell / shell structure, the first shell portion is ZnSe, the second shell portion is ZnS, and the inner core portion is InP. Nanocrystal particles, core / shell / Nanocrystal particles having a shell structure, the first shell portion is a mixed crystal of ZnS and ZnSe, the second shell portion is ZnS, and the inner core portion is InP. And so on.

Examples of the green-emitting semiconductor nanocrystal particles include CdSe nanocrystal particles, mixed-crystal nanocrystal particles of CdSe and ZnS, and nanocrystal particles having a core / shell structure, and the shell portion is ZnS. Nanocrystal particles whose inner core is InP, nanocrystals having a core / shell structure, whose shell is a mixed crystal of ZnS and ZnSe, and whose inner core is InP. Crystal particles, nanocrystal particles having a core / shell / shell structure, in which the first shell portion is ZnSe, the second shell portion is ZnS, and the inner core portion is InP. , Nanocrystal particles with a core / shell / shell structure, the first shell part is a mixed crystal of ZnS and ZnSe, the second shell part is ZnS, and the inner core part is InP. Examples include certain nanocrystal particles.

The blue-emitting semiconductor nanocrystal particles include, for example, ZnSe nanocrystal particles, ZnS nanocrystal particles, and nanocrystal particles having a core / shell structure, and the shell portion is ZnSe and the inner core portion. Is ZnS, nanocrystal particles of CdS, and nanocrystal particles having a core / shell structure. The shell portion is ZnS and the inner core portion is InP. Nanocrystal particles, core / shell Nanocrystal particles having a structure, in which the shell portion is a mixed crystal of ZnS and ZnSe and the inner core portion is InP, and the nanocrystal particles have a core / shell / shell structure. The first shell portion is ZnSe, the second shell portion is ZnS, the inner core portion is InP, and the nanocrystal particles have a core / shell / shell structure. Examples thereof include nanocrystal particles in which the first shell portion is a mixed crystal of ZnS and ZnSe, the second shell portion is ZnS, and the inner core portion is InP.

The semiconductor nanocrystal particles have the same chemical composition, and by changing the average particle diameter of the particles themselves, the color to be emitted from the particles can be changed to red or green. Further, it is preferable to use semiconductor nanocrystal particles that have as little adverse effect on the human body as possible. When semiconductor nanocrystal particles containing cadmium, selenium, etc. are used as luminescent nanocrystal particles, semiconductor nanocrystal particles containing the above elements (cadmium, selenium, etc.) as little as possible are selected and used alone, or the above elements. It is preferable to use it in combination with other luminescent nanocrystal particles so that the amount of selenium is as small as possible.

The shape of the luminescent nanocrystal particles is not particularly limited, and may be any geometric shape or any irregular shape. The shape of the luminescent nanocrystal particles may be, for example, spherical, ellipsoidal, pyramidal, disk-shaped, branched, net-shaped, rod-shaped, or the like. However, as the luminescent nanocrystal particles, using particles having less directional particle shape (for example, spherical or tetrahedral particles) can further improve the uniformity and fluidity of the ink composition. Is preferable.

The average particle diameter (volume average diameter) of the luminescent nanocrystal particles may be 1 nm or more, and may be 1.5 nm from the viewpoint of easily obtaining light emission of a desired wavelength and excellent dispersibility and storage stability. It may be more than 2 nm and may be 2 nm or more. From the viewpoint that a desired emission wavelength can be easily obtained, it may be 40 nm or less, 30 nm or less, or 20 nm or less. The average particle diameter (volume average diameter) of the luminescent nanocrystal particles is obtained by measuring with a transmission electron microscope or a scanning electron microscope and calculating the volume average diameter.

From the viewpoint of dispersion stability, the luminescent nanocrystal particles preferably have an organic ligand on the surface thereof. The organic ligand may be coordinated, for example, to the surface of the luminescent nanocrystal particles. In other words, the surface of the luminescent nanocrystal particles may be passivated by an organic ligand. Further, when the ink composition further contains a polymer dispersant described later, the luminescent nanocrystal particles may have a polymer dispersant on the surface thereof. In the present embodiment, for example, the organic ligand is removed from the luminescent nanocrystal particles having the above-mentioned organic ligand, and the organic ligand is exchanged with the polymer dispersant to cause the polymer dispersant on the surface of the luminescent nanocrystal particles. May be combined. However, from the viewpoint of dispersion stability when the ink is used as an inkjet ink, it is preferable that the polymer dispersant is blended with the luminescent nanocrystal particles in which the organic ligand is still coordinated.

Examples of the organic ligand include a functional group for ensuring affinity with a photopolymerizable compound, a thermosetting resin, an organic solvent, etc. (hereinafter, also simply referred to as "affinity group"), and luminescent nanocrystal particles. It is preferable that the compound has a functional group that can be bonded (a functional group for ensuring the adsorptivity to luminescent nanocrystal particles). The affinity group may be a substituted or unsubstituted aliphatic hydrocarbon group. The aliphatic hydrocarbon group may be a linear type or may have a branched structure. Further, the aliphatic hydrocarbon group may have an unsaturated bond or may not have an unsaturated bond. The substituted aliphatic hydrocarbon may be a group in which some carbon atoms of the aliphatic hydrocarbon group are substituted with oxygen atoms. The substituted aliphatic hydrocarbon group may contain, for example, a (poly) oxyalkylene group. Here, the "(poly) oxyalkylene group" means at least one of an oxyalkylene group and a polyoxyalkylene group in which two or more alkylene groups are linked by an ether bond. Examples of the functional group capable of binding to the luminescent nanocrystal particles include a hydroxyl group, an amino group, a carboxyl group, a thiol group, a phosphoric acid group, a phosphonic acid group, a phosphine group, a phosphine oxide group and an alkoxysilyl group. Examples of the organic ligand include TOP (trioctylphosphine), TOPO (trioctylphosphine oxide), oleic acid, phosphonic acid, linolenic acid, ricinolic acid, gluconic acid, 16-hydroxyhexadecanoic acid, 12-hydroxystearic acid, N. -Lauroyl sarcosin, N-oleyl sarcosin, oleyl amine, octylamine, trioctylamine, hexadecylamine, octanethiol, dodecanethiol, hexylphosphonic acid (HPA), tetradecylphosphonic acid (TDPA), phenylphosphonic acid, and octylphosphine. Acid (OPA) can be mentioned.

［式（１−１）中、ｐは０〜５０の整数を示し、ｑは０〜５０の整数を示す。］ In one embodiment, the organic ligand may be an organic ligand represented by the following formula (1-1).

[In equation (1-1), p represents an integer from 0 to 50, and q represents an integer from 0 to 50. ]

In the organic ligand represented by the formula (1-1), at least one of p and q is preferably 1 or more, and both p and q are more preferably 1 or more.

The organic ligand may be, for example, an organic ligand represented by the following formula (1-2).

In formula (1-2), A ¹ represents a monovalent group containing a carboxyl group, A ² represents a monovalent group containing a hydroxyl group, and R is a hydrogen atom, a methyl group, or an ethyl group. , L represents a substituted or unsubstituted alkylene group, and r represents an integer of 0 or more. The number of carboxyl groups in a monovalent group containing a carboxyl group may be 2 or more, 2 or more and 4 or less, and may be 2. The carbon number of the alkylene group represented by L may be, for example, 1 to 10. The alkylene group represented by L may be partially substituted with a hetero atom, and may be substituted with at least one hetero atom selected from the group consisting of an oxygen atom, a sulfur atom and a nitrogen atom. May be good. r may be, for example, an integer of 1 to 100, or may be an integer of 10 to 20.

The organic ligand may be an organic ligand represented by the following formula (1-2A) from the viewpoint of excellent external quantum efficiency of the pixel portion (cured product of the ink composition).

In formula (1-2A), r is synonymous with the above.

The content of the organic ligand in the ink composition is 15 parts by mass or more and 20 parts by mass with respect to 100 parts by mass of the luminescent nanocrystal particles from the viewpoint of dispersion stability of the luminescent nanocrystal particles and maintenance of luminescence characteristics. As mentioned above, it may be 25 parts by mass or more, 30 parts by mass or more, 35 parts by mass or more, or 40 parts by mass or more. The content of the organic ligand in the ink composition is 50 parts by mass or less, 45 parts by mass or less, 40 parts by mass or less, or 40 parts by mass or less with respect to 100 parts by mass of the luminescent nanocrystal particles from the viewpoint of easily keeping the viscosity of the ink composition low. It may be 30 parts by mass or less.

As the luminescent nanocrystal particles, those dispersed in a colloidal form in an organic solvent, a photopolymerizable compound, or the like can be used. The surface of the luminescent nanocrystal particles dispersed in an organic solvent is preferably passivated by the above-mentioned organic ligand. As the organic solvent, the organic solvent described later contained in the ink composition is used.

Commercially available products can be used as the luminescent nanocrystal particles. Examples of commercially available luminescent nanocrystal particles include indium phosphide / zinc sulfide, D-dot, CuInS / ZnS from NN-Labs, and InP / ZnS from Aldrich.

The content of the luminescent nanocrystal particles is preferably 5 parts by mass or more with respect to 100 parts by mass in total of the components other than the organic solvent contained in the ink composition from the viewpoint of further improving the external quantum efficiency of the pixel portion. Yes, it may be 10 parts by mass or more, 15 parts by mass or more, 20 parts by mass or more, or 30 parts by mass or more. The content of the luminescent nanocrystal particles is preferably 80 with respect to a total of 100 parts by mass of the components other than the organic solvent contained in the ink composition from the viewpoint of further improving ejection stability and external quantum efficiency of the pixel portion. It may be 75 parts by mass or less, 70 parts by mass or less, or 60 parts by mass or less. In the present specification, "components other than the organic solvent contained in the ink composition" may be paraphrased as components to be contained in the cured product of the ink composition. The "total of the components other than the organic solvent contained in the ink composition" includes, for example, luminescent nanocrystal particles, an organic ligand, a photopolymerizable compound and / or a thermosetting resin, and light scattering particles. It can be a total.

The content of the luminescent nanocrystal particles based on the total mass of the ink composition is preferably 15% by mass or more, 18% by mass or more, or 20% by mass or more from the viewpoint of further improving the external quantum efficiency. You may. The content of the luminescent nanocrystal particles based on the total mass of the ink composition is preferably 35% by mass or less, and 32% by mass or less or 30% by mass, from the viewpoint of improving ejection stability and external quantum efficiency. It may be as follows.

The ink composition may contain two or more of red-emitting nanocrystal particles, green-emitting nanocrystal particles, and blue-emitting nanocrystal particles as the luminescent nanocrystal particles, but these are preferable. Contains only one of the particles. When the ink composition contains red luminescent nanocrystal particles, the content of the green luminescent nanocrystal particles and the content of the blue luminescent nanocrystal particles are preferably 10 based on the total mass of the luminescent nanocrystal particles. It is not more than mass%, more preferably 0 mass%. When the ink composition contains green luminescent nanocrystal particles, the content of the red luminescent nanocrystal particles and the content of the blue luminescent nanocrystal particles are preferably 10 based on the total mass of the luminescent nanocrystal particles. It is not more than mass%, more preferably 0 mass%.

[Photopolymerizable compound]
The photopolymerizable compound is a compound that polymerizes by irradiation with light, and is, for example, a photoradical polymerizable compound or a photocationic polymerizable compound. The photopolymerizable compound may be a photopolymerizable monomer or oligomer. These are used with photopolymerization initiators. Photoradical polymerizable compounds are used with photoradical polymerization initiators and photocationic polymerizable compounds are used with photocationic polymerization initiators. In other words, the ink composition may contain a photopolymerizable component containing a photopolymerizable compound and a photopolymerization initiator, and may contain a photoradical polymerizable component containing a photoradical polymerizable compound and a photoradical polymerization initiator. It may be contained, or may contain a photocationic polymerizable component containing a photocationic polymerizable compound and a photocationic polymerization initiator. A photoradical polymerizable compound and a photocationic polymerizable compound may be used in combination, or a compound having photoradical polymerizable property and photocationic polymerizable property may be used, and a photoradical polymerization initiator and a photocationic polymerization initiator May be used together. One type of photopolymerizable compound may be used alone, or two or more types may be used in combination.

Examples of the photoradical polymerizable compound include a monomer having an ethylenically unsaturated group (hereinafter, also referred to as “ethylenically unsaturated monomer”), a monomer having an isocyanate group, and the like. Here, the ethylenically unsaturated monomer means a monomer having an ethylenically unsaturated bond (carbon-carbon double bond). Examples of the ethylenically unsaturated monomer include a monomer having an ethylenically unsaturated group such as a vinyl group, a vinylene group, and a vinylidene group. Monomers having these groups may be referred to as "vinyl monomers".

The number of ethylenically unsaturated bonds (for example, the number of ethylenically unsaturated groups) in the ethylenically unsaturated monomer is, for example, 1-3. One type of ethylenically unsaturated monomer may be used alone, or a plurality of types may be used in combination. The photopolymerizable compound has one or two ethylenically unsaturated groups from the viewpoint of facilitating both excellent ejection stability and excellent curability and further improving the external quantum efficiency. It may contain a monomer and a monomer having two or three ethylenically unsaturated groups. That is, the ethylenically unsaturated monomer is selected from at least a group consisting of a monofunctional monomer and a bifunctional monomer, a monofunctional monomer and a trifunctional monomer, a bifunctional monomer and a bifunctional monomer, and a bifunctional monomer and a trifunctional monomer. It may contain one combination.

Examples of the ethylenically unsaturated group include a vinyl group, a vinylene group, a vinylidene group, and a (meth) acryloyl group. In addition, in this specification, a "(meth) acryloyl group" means an "acryloyl group" and a corresponding "methacryloyl group". The same applies to the expressions "(meth) acrylate" and "(meth) acrylamide".

The photopolymerizable compound preferably contains a compound having a (meth) acryloyl group as an ethylenically unsaturated group, and more preferably a (meth) acrylate compound and a (meth) acrylamide compound.

Examples of the monofunctional monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, amyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and octyl (meth). Acrylate, nonyl (meth) acrylate, dodecyl (meth) acrylate, hexadecyl (meth) acrylate, octadecyl (meth) acrylate, cyclohexyl (meth) acrylate, methoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, phenoxyethyl (meth) ) Acrylate, nonylphenoxyethyl (meth) acrylate, glycidyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, ethoxyethoxyethyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (Meta) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2-hydroxyethyl ( Meta) acrylate, benzyl (meth) acrylate, phenylbenzyl (meth) acrylate, monosuccinate (2-acryloyloxyethyl), monosuccinate (2-methacryloyloxyethyl), N- [2- (acryloyloxy) ethyl] Phthramimide, N- [2- (acryloyloxy) ethyl] tetrahydrophthalimide, 4-hydroxybutyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl acrylate, acrylamide, N-isopropylacrylamide, N, N-dimethylacrylamide, N, N-diethylacrylamide, diacetoneacrylamide, 4-acryloylmorpholine, N-tert-butylacrylamide, N-hydroxymethylacrylamide, N-hydroxyethylacrylamide, N-tert-octylacrylamide, N-butoxymethylacrylamide, N-phenylacrylamide , N-dodecylacrylamide and the like. Among these, ethoxyethoxyethyl (meth) acrylate and diacetone acrylamide are preferably used.

Specific examples of the monomer having two ethylenically unsaturated groups (bifunctional monomer) include 1,3-butylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, and 1,5-pentane. Dioldi (meth) acrylate, 3-methyl-1,5-pentanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,8-octanediol Di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, tricyclodecanedimethanol di (meth) acrylate, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate ) Acrylic, Dipropylene glycol di (meth) acrylate, Tripropylene glycol di (meth) acrylate, Polypropylene glycol di (meth) acrylate, Neopentylglycol hydroxypivalate diacryllate, Tris (2-hydroxyethyl) ) Di (meth) acrylate in which the two hydroxyl groups of isocyanurate are substituted with (meth) acryloyloxy groups, and two diols obtained by adding 4 mol or more of ethylene oxide or propylene oxide to 1 mol of neopentyl glycol. Di (meth) acrylate in which the hydroxyl group of is substituted with a (meth) acryloyloxy group, and two hydroxyl groups of a diol obtained by adding 2 mol of ethylene oxide or propylene oxide to 1 mol of bisphenol A are (meth) acryloyloxy groups. Di (meth) acrylate substituted with (meth) Acryloyloxy group substituted with (meth) acryloyloxy group at 2 hydroxyl groups of triol obtained by adding 3 mol or more of ethylene oxide or propylene oxide to 1 mol of trimethylolpropane. Di (meth) acrylate, N, N'in which the two hydroxyl groups of the diol obtained by adding 4 mol or more of ethylene oxide or propylene oxide to 1 mol of meta) acrylate and bisphenol A are substituted with (meth) acryloyloxy groups. -Methylenebisacrylamide, N, N'-ethylenebisacrylamide and the like can be mentioned. Among these, dipropylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, and 1,6-hexanediol diacrylate are preferably used.

Specific examples of the monomer having three ethylenically unsaturated groups (trifunctional monomer) include glycerin tri (meth) acrylate and trimethylolethane tri (meth) acrylate. Among these, glycerin tri (meth) acrylate is preferably used.

Examples of the photocationically polymerizable compound include epoxy compounds, oxetane compounds, vinyl ether compounds and the like.

Examples of the epoxy compound include aliphatic epoxy compounds such as bisphenol A type epoxy compound, bisphenol F type epoxy compound, phenol novolac type epoxy compound, trimethylolpropane polyglycidyl ether, and neopentyl glycol diglycidyl ether, 1,2-epoxy-. Examples thereof include alicyclic epoxy compounds such as 4-vinylcyclohexane and 1-methyl-4- (2-methyloxylanyl) -7-oxabicyclo [4.1.0] heptane.

It is also possible to use a commercially available product as the epoxy compound. As a commercially available epoxy compound, for example, "Celoxide 2000", "Celoxide 3000", "Celoxide 4000", etc. manufactured by Daicel Chemical Industries, Ltd. can be used.

Cationicly polymerizable oxetane compounds include 2-ethylhexyl oxetane, 3-hydroxymethyl-3-methyloxetane, 3-hydroxymethyl-3-ethyloxetane, 3-hydroxymethyl-3-propyloxetane, and 3-hydroxymethyl-3. -Normal butyl oxetane, 3-hydroxymethyl-3-phenyloxetane, 3-hydroxymethyl-3-benzyloxetane, 3-hydroxyethyl-3-methyloxetane, 3-hydroxyethyl-3-ethyloxetane, 3-hydroxyethyl- 3-propyl oxetane, 3-hydroxyethyl-3-phenyloxetane, 3-hydroxypropyl-3-methyloxetane, 3-hydroxypropyl-3-ethyloxetane, 3-hydroxypropyl-3-propyl oxetane, 3-hydroxypropyl- Examples thereof include 3-phenyloxetane and 3-hydroxybutyl-3-methyloxetane.

It is also possible to use a commercially available product as an oxetane compound. Examples of commercially available oxetane compounds include Aron oxetane series manufactured by Toa Synthetic Co., Ltd. ("OXT-101", "OXT-212", "OXT-121", "OXT-221", etc.); Daicel Chemical Industry Co., Ltd. Company-made "Selokiside 2021", "Selokiside 2021A", "Selokiside 2021P", "Selokiside 2080", "Selokiside 2081", "Selokiside 2083", "Selokiside 2085", "Epolide GT300", "Epolide GT301" "GT302", "Epolide GT400", "Epolide GT401" and "Epolide GT403"; "Cyracure UVR-6105", "Cyracure UVR-6107", "Cyracure UVR-6110", "Cyracure UVR" manufactured by Dow Chemical Japan Co., Ltd. -6128, "ERL4289", "ERL4299" and the like can be used. Further, a known oxetane compound (for example, the oxetane compound described in JP-A-2009-40830) can also be used.

Examples of the vinyl ether compound include 2-hydroxyethyl vinyl ether, triethylene glycol vinyl monoether, tetraethylene glycol divinyl ether, and trimethylolpropane trivinyl ether.

Further, as the photopolymerizable compound in the present embodiment, the photopolymerizable compounds described in paragraphs 0042 to 0049 of JP2013-182215A can also be used.

In the present embodiment, the photopolymerizable compound preferably contains an N-vinyl compound from the viewpoint of further improving the external quantum efficiency and obtaining a more remarkable effect of reducing the wavelength shift. The N-vinyl compound is a compound having a nitrogen atom and a vinyl group directly bonded to the nitrogen atom. The molecular weight of the N-vinyl compound is, for example, 70 or more and 400 or less.

Specific examples of the N-vinyl compound include N-vinyl-ε-caprolactam, N-vinylpyrrolidone, N-vinylimidazole, N-vinylcarbazole, N-vinylmorpholine, N-vinylacetamide, and N-vinyl-N-. Examples thereof include methylacetamide, N-vinylformamide, N-vinyl-5-methyl-2-oxazolidinone and the like. Among these, it is preferable that the photopolymerizable compound contains N-vinyl-ε-caprolactam and / or N-vinylpyrrolidone from the viewpoint of easily dissolving the zinc compound and easily obtaining the above-mentioned effects.

When the photopolymerizable compound contains an N-vinyl compound, the photopolymerizable compound preferably contains a photopolymerizable compound other than the N-vinyl compound. Examples of other photopolymerizable compounds include monofunctional monomers, bifunctional monomers, and the compounds described above as trifunctional monomers. From the viewpoint of facilitating curing at room temperature quickly and without heating, it is more preferable to use the N-vinyl compound and the (meth) acrylate compound in combination. By using the N-vinyl compound in combination with the (meth) acrylate compound, the curability can be enhanced and the cured product can be cured quickly, and the tackiness of the cured product (for example, a cured film) can be reduced. There is a tendency to obtain an effect that blocking that occurs when a glass base material is laminated on the glass can be suppressed. The addition amount for obtaining this effect is the same as the above addition amount.

The content of the N-vinyl compound in the photopolymerizable compound is based on the total mass of the photopolymerizable compound from the viewpoint that the effect of improving the external quantum efficiency can be easily obtained and the effect of reducing the wavelength shift can be obtained more remarkably. , 0.1% by mass or more, 1% by mass or more, or 5% by mass or more. The content of the N-vinyl compound in the photopolymerizable compound is 50% by mass from the viewpoint of obtaining sufficient curability, reducing the viscosity of the ink composition to a low viscosity, and suppressing the volatility of the ink composition. Hereinafter, it may be 40% by mass or less or 30% by mass or less. The content of the N-vinyl compound in the ink composition is other than the organic solvent contained in the ink composition from the viewpoint that the effect of improving the external quantum efficiency can be easily obtained and the effect of reducing the wavelength shift can be obtained more remarkably. The total amount of the components may be 0.05 parts by mass or more, 0.5 parts by mass or more, or 2 parts by mass or more with respect to 100 parts by mass. In addition, the content of the N-vinyl compound in the ink composition is 35 mass from the viewpoint of obtaining sufficient curability, reducing the viscosity of the ink composition to low viscosity, and suppressing the volatility of the ink composition. It may be less than a part, 25 parts by mass or less, or 20 parts by mass or less.

The photopolymerizable compound may be alkali-insoluble from the viewpoint that a highly reliable pixel portion (cured product of the ink composition) can be easily obtained. In the present specification, the fact that the photopolymerizable compound is alkali-insoluble means that the amount of the photopolymerizable compound dissolved in 1% by mass of an aqueous potassium hydroxide solution at 25 ° C. is 30 based on the total mass of the photopolymerizable compound. It means that it is mass% or less. The dissolved amount of the photopolymerizable compound is preferably 10% by mass or less, and more preferably 3% by mass or less.

The content of the photopolymerizable compound is determined from the viewpoint that an appropriate viscosity can be easily obtained as an inkjet ink, the viewpoint of improving the curability of the ink composition, and the solvent resistance of the pixel portion (cured product of the ink composition). From the viewpoint of improving the abrasion resistance, the total amount of the components other than the organic solvent contained in the ink composition may be 10 parts by mass or more, or 15 parts by mass or more. It may be 20 parts by mass or more. The content of the photopolymerizable compound is other than the organic solvent contained in the ink composition from the viewpoint that an appropriate viscosity can be easily obtained as an inkjet ink and from the viewpoint of obtaining more excellent optical characteristics (for example, external quantum efficiency). With respect to a total of 100 parts by mass of the components, it may be 60 parts by mass or less, 50 parts by mass or less, 40 parts by mass or less, 30 parts by mass or less, 20 parts by mass. It may be less than a part by mass.

[Photopolymerization initiator]
The photopolymerization initiator is, for example, a photoradical polymerization initiator or a photocationic polymerization initiator. As the photoradical polymerization initiator, a molecular cleavage type or hydrogen abstraction type photoradical polymerization initiator is suitable.

Examples of the molecular cleavage type photoradical polymerization initiator include benzoin isobutyl ether, 2,4-diethylthioxanthone, 2-isopropylthioxanthone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and 2-benzyl-2-dimethylamino-1. -(4-morpholinophenyl) -butane-1-one, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, (2,4,6-trimethylbenzoyl) ethoxyphenylphosphine oxide Etc. are preferably used. Other molecular cleavage type photoradical polymerization initiators include 1-hydroxycyclohexylphenyl ketone, benzoin ethyl ether, benzyl dimethyl ketal, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4). -Isopropylphenyl) -2-hydroxy-2-methylpropan-1-one and 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1-one may be used in combination.

Examples of the hydrogen abstraction type photoradical polymerization initiator include benzophenone, 4-phenylbenzophenone, isophthalphenone, 4-benzoyl-4'-methyl-diphenylsulfide and the like. A molecular cleavage type photoradical polymerization initiator and a hydrogen abstraction type photoradical polymerization initiator may be used in combination.

A commercially available product can also be used as the photocationic polymerization initiator. Commercially available products include sulfonium salt-based photocationic polymerization initiators such as "CPI-100P" manufactured by San-Apro, acylphosphine oxide compounds such as "Lucirin TPO" manufactured by BASF, and "Irgacure 907" manufactured by BASF. Examples thereof include "Irgacure 819", "Irgacure 379EG", ", Irgacure 184" and "Irgacure PAG290".

The content of the photopolymerization initiator may be 0.1 part by mass or more and 0.5 part by mass or more with respect to 100 parts by mass of the photopolymerizable compound from the viewpoint of curability of the ink composition. It may be 1 part by mass or more, 3 parts by mass or more, or 5 parts by mass or more. The content of the photopolymerization initiator may be 40 parts by mass or less, and 30 parts by mass with respect to 100 parts by mass of the photopolymerizable compound, from the viewpoint of the temporal stability of the pixel portion (cured product of the ink composition). It may be 20 parts by mass or less, 10 parts by mass or less.

[Thermosetting resin]
In the present embodiment, the thermosetting resin is a resin that is crosslinked and cured by heat. The thermosetting resin is, for example, a resin that functions as a binder in a cured product. Thermosetting resins have curable groups. Examples of the curable group include an epoxy group, an oxetane group, an isocyanate group, an amino group, a carboxyl group, a methylol group, and the like, from the viewpoint of excellent heat resistance and storage stability of the cured product of the ink composition, and a light-shielding portion (light-shielding portion). For example, an epoxy group is preferable from the viewpoint of excellent adhesion to the black matrix) and the substrate. The thermosetting resin may have one kind of curable group or may have two or more kinds of curable groups.

Among the thermosetting resins, a resin having photoradical polymerization (polymerized by irradiation with light when used together with a photoradical polymerization initiator) and a photocationic polymerizable resin (photocationic polymerization). Contains resins (polymerized by light irradiation when used with an initiator). When the ink composition contains a thermosetting resin having photoradical polymerization property and a photoradical polymerization initiator, the thermosetting resin having photoradical polymerization property becomes a photoradical polymerizable compound (photopolymerizable compound). It shall be classified. When the ink composition contains a photocationically polymerizable thermosetting resin and a photocationic polymerization initiator, the photocationically polymerizable thermosetting resin becomes a photocationically polymerizable compound (photopolymerizable compound). It shall be classified.

The thermosetting resin may be a polymer (homopolymer) of a single monomer, or may be a copolymer (copolymer) of a plurality of types of monomers. Further, the thermosetting resin may be any of a random copolymer, a block copolymer and a graft copolymer.

As the thermosetting resin, a compound having two or more thermosetting groups in one molecule is used, and it is usually used in combination with a curing agent. When a thermosetting resin is used, a catalyst (curing accelerator) capable of accelerating the thermosetting reaction may be further added. In other words, the ink composition may contain a thermosetting component containing a thermosetting resin (as well as a curing agent and a curing accelerator used as needed). In addition to these, a polymer that does not have a polymerization reactivity by itself may be further used.

As the compound having two or more thermosetting groups in one molecule, for example, an epoxy resin having two or more epoxy groups in one molecule (hereinafter, also referred to as “polyfunctional epoxy resin”) may be used. The "epoxy resin" includes both a monomeric epoxy resin and a polymeric epoxy resin. The number of epoxy groups contained in one molecule of the polyfunctional epoxy resin is preferably 2 to 50, more preferably 2 to 20. The epoxy group may have a structure having an oxylan ring structure, and may be, for example, a glycidyl group, an oxyethylene group, an epoxycyclohexyl group, or the like. Examples of the epoxy resin include known polyvalent epoxy resins that can be cured by a carboxylic acid. Such epoxy resins are widely disclosed in, for example, "Epoxy Resin Handbook" edited by Masaki Shinbo, published by Nikkan Kogyo Shimbun (1987), and these can be used.

Examples of the thermosetting resin having an epoxy group (including a polyfunctional epoxy resin) include a polymer of a monomer having an oxylan ring structure and a copolymer of a monomer having an oxylan ring structure and another monomer. Specific polyfunctional epoxy resins include polyglycidyl methacrylate, methyl methacrylate-glycidyl methacrylate copolymer, benzyl methacrylate-glycidyl methacrylate copolymer, n-butyl methacrylate-glycidyl methacrylate copolymer, and 2-hydroxyethyl methacrylate-glycidyl. Examples thereof include a methacrylate copolymer, a (3-ethyl-3-oxetanyl) methyl methacrylate-glycidyl methacrylate copolymer, and a styrene-glycidyl methacrylate. Further, as the thermosetting resin of the present embodiment, the compounds described in paragraphs 0044 to 0066 of JP-A-2014-562248 can also be used.

Examples of the polyfunctional epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, brominated bisphenol A type epoxy resin, bisphenol S type epoxy resin, diphenyl ether type epoxy resin, hydroquinone type epoxy resin, and naphthalene type epoxy. Resin, biphenyl type epoxy resin, fluorene type epoxy resin, phenol novolac type epoxy resin, orthocresol novolac type epoxy resin, trishydroxyphenylmethane type epoxy resin, trifunctional epoxy resin, tetraphenylol ethane type epoxy resin, dicyclopentadiene Phenol type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol A nucleated polyol type epoxy resin, polypropylene glycol type epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, glioxal type epoxy resin, alicyclic epoxy resin , Heterocyclic epoxy resin and the like can be used.

More specifically, a bisphenol A type epoxy resin such as the product name "Epicoat 828" (manufactured by Japan Epoxy Resin Co., Ltd.), a bisphenol F type epoxy resin such as the product name "YDF-175S" (manufactured by Toto Kasei Co., Ltd.), and a product name. Brominated bisphenol A type epoxy resin such as "YDB-715" (manufactured by Toto Kasei Co., Ltd.), bisphenol S type epoxy resin such as trade name "EPICLON EXA1514" (manufactured by DIC Co., Ltd.), trade name "YDC-1312" (Toto) Hydroquinone type epoxy resin such as (manufactured by Kasei Co., Ltd.), Naphthalene type epoxy resin such as product name "EPICLON EXA4032", "HP-4770", "HP-4700", "HP-5000" (manufactured by DIC Co., Ltd.), product name Biphenyl type epoxy resin such as "Epicoat YX4000H" (manufactured by Japan Epoxy Resin), bisphenol A type novolac epoxy resin such as product name "Epicoat 157S70" (manufactured by Japan Epoxy Resin), product name "Epicoat 154" (Japan Epoxy) Resin company), phenol novolac type epoxy resin such as product name "YDPN-638" (manufactured by Toto Kasei Co., Ltd.), cresol novolac type epoxy resin such as product name "YDCN-701" (manufactured by Toto Kasei company), product name " Dicyclopentadienephenol type epoxy resin such as "EPICLON HP-7200" and "HP-7200H" (manufactured by DIC Co., Ltd.), Trishydroxyphenylmethane type epoxy resin such as trade name "Epicoat 1032H60" (manufactured by Japan Epoxy Resin), Trifunctional epoxy resin such as product name "VG3101M80" (manufactured by Mitsui Chemicals), tetraphenylol ethane type epoxy resin such as product name "Epicoat 1031S" (manufactured by Japan Epoxy Resin), product name "Denacol EX-411" 4-functional epoxy resin such as (Nagase Kasei Kogyo Co., Ltd.), hydrogenated bisphenol A type epoxy resin such as product name "ST-3000" (manufactured by Toto Kasei Co., Ltd.), product name "Epicoat 190P" (manufactured by Japan Epoxy Resin) ) Etc., glycidyl ester type epoxy resin such as trade name "YH-434" (manufactured by Toto Kasei Co., Ltd.), glycidyl amine type epoxy resin such as trade name "YDG-414" (manufactured by Toto Kasei Co., Ltd.), Triglycidyl isocyanate, an alicyclic polyfunctional epoxy compound such as the product name "Epolide GT-401" (manufactured by Daicel Chemical Co., Ltd.) Heterocyclic epoxy resins such as TGIC) can be exemplified. If necessary, a trade name "Neo Tote E" (manufactured by Toto Kasei Co., Ltd.) or the like can be mixed as an epoxy-reactive diluent.

As the polyfunctional epoxy resin, "Findick A-247S", "Findick A-254", "Findick A-253", "Findick A-229-30A", "Fine Dick A-229-30A" manufactured by DIC Corporation "Dic A-261", "Find Dick A249", "Find Dick A-266", "Find Dick A-241", "Find Dick M-8020", "EPICLON N-740", "EPICLON N-770", " "EPICLON N-865", "EPICLON EXA-4850-150" (trade name) and the like can be used.

The weight average molecular weight of the thermosetting resin is from the viewpoint that an appropriate viscosity can be easily obtained as an inkjet ink, from the viewpoint of improving the curability of the ink composition, and the solvent resistance of the pixel portion (cured product of the ink composition). And from the viewpoint of improving the abrasion resistance, it may be 750 or more, 1000 or more, or 2000 or more. From the viewpoint of obtaining an appropriate viscosity as an inkjet ink, it may be 500,000 or less, 300,000 or less, or 200,000 or less. However, this does not apply to the molecular weight after cross-linking.

The content of the thermosetting resin includes the viewpoint that an appropriate viscosity can be easily obtained as an inkjet ink, the viewpoint that the curability of the ink composition is good, the solvent resistance of the pixel portion (cured product of the ink composition), and the solvent resistance. From the viewpoint of improving the abrasion resistance, the total amount of the components other than the organic solvent contained in the ink composition may be 5 parts by mass or more, 10 parts by mass or more, and 15 parts by mass. It may be 20 parts by mass or more. The content of the thermosetting resin is a component other than the organic solvent contained in the ink composition from the viewpoint that the viscosity of the ink composition does not become too high and the thickness of the pixel portion does not become too thick for the light conversion function. It may be 60 parts by mass or less, 50 parts by mass or less, 40 parts by mass or less, 30 parts by mass or less, or 20 parts by mass with respect to 100 parts by mass in total. It may be less than or equal to a part.

[Hardener]
Examples of the curing agent used for curing the thermosetting resin include acid anhydrides, phenolic compounds, amine compounds and the like. These curing agents may be used alone or in combination of two or more. The curing agent preferably contains at least one selected from the group consisting of acid anhydrides, phenolic compounds and amine compounds. When the epoxy resin is used as the thermosetting resin, it may be self-polymerized using onium salts, organometallic complexes, tertiary amines, imidazoles and the like.

Examples of the acid anhydride (acid anhydride-based curing agent) include 4-methylcyclohexane-1,2-dicarboxylic acid anhydride (4M-HHPA), 3-methylcyclohexane-1,2-dicarboxylic acid anhydride, and cyclohexane-1. , 2-Dicarboxylic Acid Anhydride, 1,2,3,6-Tetrahydrophthalic anhydride, 3-Methyl-1,2,3,6-Tetrahydrophthalic anhydride, 4-Methyl-1,2,3,6- Tetrahydrophthalic anhydride, bicyclo [2.2.1] heptane-2,3-dicarboxylic acid anhydride, methylbicyclo [2.2.1] heptane-2,3-dicarboxylic acid anhydride, methyl-3,6 end Methylene-1,2,3,6-tetrahydrophthalic anhydride, 3,6 endomethylene-1,2,3,6-tetrahydrophthalic anhydride, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleine anhydride Acids and the like can be mentioned.

Examples of phenolic compounds (phenolic curing agents) include bisphenol A, bisphenol F, bisphenol S, resorcin, catechol, hydroquinone, fluorene bisphenol, 4,4'-biphenol, 4,4', 4 "-trihydroxytriphenylmethane. , Naphthalenediol, 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, calix arene, novolak type phenolic resin (eg, phenol novolac resin, cresol novolak resin, bisphenol A novolak resin, bisphenol S novolak resin, resorcin Polyvalent phenol novolac resin synthesized from polyvalent hydroxy compounds typified by novolak resin and formaldehyde, naphthol-phenol co-condensed novolak resin, naphthol-cresol co-condensed novolak resin, naphthol novolak resin, and alkoxy group-containing aromatic ring modification Novolac resin (a polyvalent phenol compound in which a phenol nucleus and an alkoxy group-containing aromatic ring are linked with formaldehyde), aralkyl type phenol resin (for example, phenol aralkyl resin such as Zyroc resin and naphthol aralkyl resin), aromatic hydrocarbon formaldehyde resin Modified phenol resin, dicyclopentadienephenol-added resin, trimethylolmethane resin, tetraphenylol ethane resin, biphenyl-modified phenol resin (polyvalent phenol compound in which phenol nuclei are linked by bismethylene groups), biphenyl-modified naphthol resin (bismethylene groups) Polyvalent naphthol compounds with phenol nuclei linked in), polyvalent phenol compounds with aminotriazine-modified phenolic resins (polyphenol compounds with phenol nuclei linked with melamine, benzoguanamine, etc.), etc. From the viewpoint of excellent improvement effect, the phenolic compound preferably contains a novolak type phenol resin. As the novolak type phenol resin, a phenol novolak resin, a cresol novolak resin and a bisphenol A novolak resin are preferably used.

Specific examples of the novolak type phenolic resin include "PHENOLITE TD-2131" and "PHENOLITE TD-2090" (trade name) manufactured by DIC Corporation, and "GPH-65" and "GPH-103" manufactured by Nippon Kayaku Co., Ltd. "(Product name) and the like.

Examples of amine compounds (amine-based curing agents) include aliphatic polyamines such as ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, and pentaethylenehexamine, metaxylylenediamine, and diaminodiphenylmethane. Aromatic polyamines such as phenylenediamine, alicyclic polyamines such as 1,3-bis (aminomethyl) cyclohexane, isophoronediamine, norbornandiamine, etc., dimers of dicyandiamide and linolenic acid, and polyamide synthesized from ethylenediamine. Resin is mentioned.

The curing agent is preferably an acid anhydride-based curing agent from the viewpoint of heat resistance of the external quantum efficiency of the cured product of the ink composition, and from the viewpoint of the curability of the cured product of the ink composition and the viscosity stability of the ink composition. Therefore, a phenolic curing agent is desirable.

The content of the curing agent may be, for example, 40 parts by mass or less, 30 parts by mass or less, or 20 parts by mass with respect to 100 parts by mass in total of the components other than the organic solvent contained in the ink composition. It may be 10 parts by mass or less, 1 part by mass or more, or 3 parts by mass or more.

[Curing accelerator (curing catalyst)]
Examples of the curing accelerator (curing catalyst) used for curing the thermosetting resin include phosphorus compounds, tertiary amine compounds, imidazole compounds, organic acid metal salts, Lewis acids, amine complex salts and the like. .. Examples of phosphorus-based compounds include triphenylphosphine, triparatrilphosphine, diphenylcyclohexylphosphine, and methyltributylphosphonium iodide. Examples of the tertiary amine compound include N, N-dimethylbenzylamine, 1,8-diazabicyclo (5,4,0) undecene-7, 1,5-diazabicyclo (4,3,0) nonene-5, and tris. (Dimethylaminomethyl) phenol can be mentioned. Examples of the imidazole compound include 1-cyanoethyl-2-ethyl-4-methylimidazole and 2-ethyl-4-methylimidazole.

The thermosetting resin may be alkali-insoluble from the viewpoint that a pixel portion (cured product of the ink composition) having excellent reliability can be easily obtained. When the thermosetting resin is alkali-insoluble, the amount of the thermosetting resin dissolved in 1% by mass of a potassium hydroxide aqueous solution at 25 ° C. is 30% by mass or less based on the total mass of the thermosetting resin. Means that. The dissolved amount of the thermosetting resin is preferably 10% by mass or less, and more preferably 3% by mass or less.

In the present embodiment, the ink composition may contain at least one of the photopolymerizable compound and the thermosetting resin, and may contain both the photopolymerizable compound and the thermosetting resin. .. When the ink composition contains a photopolymerizable compound, it does not have to contain a thermosetting resin. Further, when the ink composition contains a thermosetting resin, it does not have to contain a photopolymerizable compound. From the viewpoint of storage stability of an ink composition containing luminescent nanocrystal particles (for example, quantum dots) and durability (wet thermosetting stability, etc.) of a pixel portion (cured product of the ink composition), a photopolymerizable compound. Of the thermosetting resins, it is preferable to use a thermosetting resin, which has a storage stability of an ink composition containing luminescent nanocrystal particles (for example, quantum dots) and a low temperature which is not easily deteriorated by heating of the quantum dots. From the viewpoint of enabling curing in, it is more preferable to use a photoradical polymerizable compound, and from the viewpoint of forming a pixel portion (cured product of an ink composition) without being hindered by oxygen in the curing process, photocationic polymerization is possible. It is preferable to use a sex compound.

When the ink composition contains a photopolymerizable compound and a thermosetting resin, the total content of the photopolymerizable compound and the thermosetting resin is determined from the viewpoint that an appropriate viscosity can be easily obtained as an inkjet ink, and the ink composition is cured. From the viewpoint of improving the properties and improving the solvent resistance and abrasion resistance of the pixel portion (cured product of the ink composition), a total of 100 parts by mass of the components other than the organic solvent contained in the ink composition. On the other hand, it may be 3 parts by mass or more, 5 parts by mass or more, 10 parts by mass or more, 15 parts by mass or more, or 20 parts by mass or more. May be good. Further, the total content of the photopolymerizable compound and the thermosetting resin does not increase the viscosity of the ink composition too much, and the thickness of the pixel portion does not become too thick for the light conversion function. It may be 60 parts by mass or less, 40 parts by mass or less, or 20 parts by mass or less with respect to a total of 100 parts by mass of the components other than the organic solvent contained in the product.

[Zinc compound]
The zinc compound of the present embodiment is a compound having a zinc atom as a central metal and having two ligands coordinated to the zinc atom. The zinc compound has one zinc atom. The zinc atom is, for example, a divalent zinc atom. In this zinc compound, each of the two ligands has a sulfur atom, and the sulfur atom is directly bonded to the zinc atom (for example, an ionic bond) to coordinate with the zinc atom. The two ligands may be the same or different from each other.

The molecular weight of the zinc compound is, for example, 700 or less. When the molecular weight of the zinc compound is 700 or less, the effect of reducing the wavelength shift tends to be obtained more remarkably, and the initial external quantum efficiency and photostability of the pixel portion tend to be more excellent. The molecular weight of the zinc compound may be 600 or less or 500 or less. The molecular weight of the zinc compound may be 200 or more from the viewpoint of easily increasing the solubility in the ink composition and easily obtaining the effect of reducing the wavelength shift.

The ligand is a compound having a coordinating functional group having a sulfur atom, and the sulfur atom of the coordinating functional group is directly bonded to the zinc atom to coordinate with the zinc atom. Examples of the coordinating functional group include a thiol group (mercapto group), a dithiocarbamic acid group, a dithiocarboxylic acid group, a thiocarboxylic acid group and the like. These coordinating functional groups are, for example, deprotonated and attached to the zinc atom. That is, the ligand may be coordinated to a zinc atom (zinc ion) in an ionized state.

Examples of the compound having a coordinating functional group include dithiocarbamic acids such as monoalkyldithiocarbamic acid, dialkyldithiocarbamic acid, diaryldithiocarbamic acid, alkylaryldithiocarbamic acid and dialalkyldithiocarbamic acid; and mercaptopyridine such as 2-mercaptopyridine N-oxide. Kind: Mercaptobenzothiazoles such as 2-mercaptobenzothiazole, mercaptobenzoxazoles such as 2-mercaptobenzoxazole, and the like. At least one of the two ligands is a dithiocarbamic acid (coordinating functionality) from the viewpoint of further improving the external quantum efficiency, further improving the photostability, and obtaining the effect of reducing the wavelength shift more remarkably. It is preferably a compound having a dithiocarbamic acid group as a group), and more preferably both of the two ligands are dithiocarbamic acids (a compound having a dithiocarbamic acid group as a coordinating functional group).

[式（Ｉ）中、Ｒ^１及びＲ^２は、それぞれ独立して、水素原子又は炭素数１〜１０の炭化水素基を示し、複数のＲ^１は互いに同一であっても異なっていてもよく、複数のＲ^２は互いに同一であっても異なっていてもよい。] As the zinc compound in which both of the two ligands are dithiocarbamic acids (compounds having a dithiocarbamic acid group as a coordinating functional group), a compound represented by the following formula (I) is preferable.

[In formula (I), R ¹ and R ² each independently represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and a plurality of R ^1s may be the same or different from each other. , A plurality of R ^2s may be the same as or different from each other. ]

The number of carbon atoms of the hydrocarbon group may be 1 to 6, and may be 1 to 4. The hydrocarbon group may be an alkyl group, an aryl group, an aralkyl group or the like, and is preferably an alkyl group. The alkyl group may be linear or branched. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group and the like. The combination of R ¹ and R ² is not particularly limited, but it is preferable that all of R ¹ and R ² are hydrocarbon groups, and it is more preferable that all of R ¹ and R ² are alkyl groups.

In formula (I), the ligand may be a monodentate ligand to the zinc atom or a bidentate ligand. That is, the compound represented by the formula (I) includes the compounds represented by the following formulas (I-1) to (I-4).

When the ink composition contains the above-mentioned N-vinyl compound, the zinc compound is preferably soluble in the N-vinyl compound from the viewpoint of further improving the external quantum efficiency. In particular, since the zinc compound tends to be difficult to dissolve in the (meth) acrylate compound, when the N-vinyl compound and the (meth) acrylate compound are used in combination, it is uniform if the zinc compound has solubility in the N-vinyl compound. It becomes easy to obtain a new ink composition, and the external quantum efficiency tends to be further improved. Specifically, the zinc compound preferably has a solubility of 1% by mass or more, more preferably 3% or more, and a solubility of 5% or more with respect to the N-vinyl compound. It is more preferable to have. The solubility of the zinc compound in the N-vinyl compound is the solubility at 23 ° C. Specifically, the N-vinyl compound and the zinc compound are mixed and dissolved by stirring at 23 ° C. for 14 hours or more. It can be obtained by the method. In this method, whether or not the zinc compound is dissolved in the N-vinyl compound is determined by whether or not precipitation of the zinc compound occurs. If there are undissolved solids (particles, etc.), the amount of dissolved zinc compound can be determined by filtering the undissolved solids with a PTFE filter and measuring the weight increase of the filter. The N-vinyl compound adhering to the filter can be volatilized and removed by reducing the pressure, and may be washed with the same amount of isopropyl acetate as the N-vinyl compound. In this case, since the zinc compound is sparingly soluble in isopropyl acetate, the effect on the evaluation of solubility can be ignored.

Commercially available products can be used as the zinc compound, and commercially available products include zinc bis (2-hydroxyethyl) dithiocarbamate, zinc (2-mercaptopyridine N-oxide), and (toluene-3,4-). Dithiorat) Zinc, bis (dibenzyldithiocarbamic acid) zinc, bis (dibutyldithiocarbamic acid) zinc, bis (diethyldithiocarbamic acid) zinc, bis (N-ethyl-N-phenyldithiocarbamic acid) zinc, bis (2-mercaptobenzothiazole) ) Zinc etc. can be used.

The content of the zinc compound is a component other than the organic solvent contained in the ink composition from the viewpoint of further improving the external quantum efficiency, further improving the photostability, and obtaining the effect of reducing the wavelength shift more remarkably. It may be 0.1 part by mass or more, 1 part by mass or more, or 2 parts by mass or more with respect to 100 parts by mass in total. The content of the zinc compound is a component other than the organic solvent contained in the ink composition from the viewpoint of further improving the external quantum efficiency, further improving the photostability, and obtaining the effect of reducing the wavelength shift more remarkably. It may be 20 parts by mass or less, 10 parts by mass or less, or 7 parts by mass or less with respect to 100 parts by mass in total.

[Light scattering particles]
The ink composition may further contain light scattering particles. The light-scattering particles are, for example, optically inactive inorganic fine particles. When the ink composition contains light-scattering particles, the light from the light source irradiated to the pixel portion can be scattered, so that excellent optical characteristics (for example, external quantum efficiency) can be obtained.

Examples of the material constituting the photoscattering particles include simple metals such as tungsten, zirconium, titanium, platinum, bismuth, rhodium, palladium, silver, tin, platinum and gold; silica, barium sulfate, barium carbonate, calcium carbonate, etc. Metal oxides such as talc, clay, kaolin, barium sulfate, barium carbonate, calcium carbonate, alumina white, titanium oxide, magnesium oxide, barium oxide, aluminum oxide, bismuth oxide, zirconium oxide, zinc oxide; magnesium carbonate, barium carbonate, Metal carbonates such as bismuth carbonate and calcium carbonate; metal hydroxides such as aluminum hydroxide; composite oxides such as barium zirconate, calcium zirconate, calcium titanate, barium titanate, strontium titanate, bismuth hyponitrate Such as metal salts and the like. The light-scattering particles are more than the group consisting of titanium oxide, alumina, zirconium oxide, zinc oxide, calcium carbonate, barium sulfate, barium titanate, and silica from the viewpoint of excellent ejection stability and the effect of improving external quantum efficiency. It is preferable to contain at least one selected, and more preferably at least one selected from the group consisting of titanium oxide, zirconium oxide, zinc oxide and barium titanate.

The shape of the light-scattering particles may be spherical, filamentous, indefinite, or the like. However, as the light-scattering particles, it is possible to use particles having less directional particle shape (for example, spherical or tetrahedral particles) to improve the uniformity, fluidity and light scattering property of the ink composition. It is preferable in that it can be enhanced and excellent discharge stability can be obtained.

The average particle diameter (volume average diameter) of the light-scattering particles in the ink composition may be 0.05 μm (50 nm) or more from the viewpoint of excellent ejection stability and the effect of improving the external quantum efficiency. , 0.2 μm (200 nm) or more, or 0.3 μm (300 nm) or more. The average particle diameter (volume average diameter) of the light-scattering particles in the ink composition may be 1.0 μm (1000 nm) or less, or 0.6 μm (600 nm) or less, from the viewpoint of excellent ejection stability. It may be 0.4 μm (400 nm) or less. The average particle diameter (volume average diameter) of the light-scattering particles in the ink composition is 0.05 to 1.0 μm, 0.05 to 0.6 μm, 0.05 to 0.4 μm, 0.2 to 1. It may be 0.0 μm, 0.2 to 0.6 μm, 0.2 to 0.4 μm, 0.3 to 1.0 μm, 0.3 to 0.6 μm, or 0.3 to 0.4 μm. From the viewpoint that such an average particle diameter (volume average diameter) can be easily obtained, the average particle diameter (volume average diameter) of the light-scattering particles used may be 0.05 μm or more, and 1.0 μm or less. You may. In the present specification, the average particle diameter (volume average diameter) of light-scattering particles in the ink composition is obtained by measuring with a dynamic light-scattering nanotrack particle size distribution meter and calculating the volume mean diameter. .. The average particle diameter (volume average diameter) of the light-scattering particles used can be obtained by measuring the particle diameter of each particle with, for example, a transmission electron microscope or a scanning electron microscope, and calculating the volume average diameter.

The content of light-scattering particles in the ink composition is 0.1 part by mass or more with respect to 100 parts by mass in total of the components other than the organic solvent contained in the ink composition from the viewpoint of being more excellent in the effect of improving the external quantum efficiency. It may be 1 part by mass or more, or 3 parts by mass or more. The content of the light-scattering particles is 60 parts by mass with respect to 100 parts by mass in total of the components other than the organic solvent contained in the ink composition from the viewpoint of excellent ejection stability and the effect of improving the external quantum efficiency. It may be less than or equal to 50 parts by mass, may be 40 parts by mass or less, may be 30 parts by mass or less, may be 25 parts by mass or less, and may be 20 parts by mass or less. It may be 15 parts by mass or less.

The content of the light-scattering particles based on the total mass of the ink composition is preferably 3% by mass or more, 4% by mass or more, or 7% by mass or more from the viewpoint of further improving the external quantum efficiency of the pixel portion. It may be. The content of the light scattering particles based on the total mass of the ink composition is preferably 20% by mass or less from the viewpoint of further improving the external quantum efficiency of the pixel portion and further improving the ejection stability. , 18% by mass or less, or 15% by mass or less.

The mass ratio of the content of the light-scattering particles to the content of the luminescent nanocrystal particles (light-scattering particles / luminescent nanocrystal particles) is 0.1 or more from the viewpoint of excellent effect of improving the external quantum efficiency. It may be 0.2 or more, or 0.5 or more. The mass ratio (light scattering particles / luminescent nanocrystal particles) may be 5.0 or less from the viewpoint of being excellent in the effect of improving the external quantum efficiency and being excellent in continuous ejection property (ejection stability) during inkjet printing. , 2.0 or less, or 1.5 or less.

The total amount of luminescent nanocrystal particles and light-scattering particles in the ink composition is 100 parts by mass in total of the components other than the organic solvent contained in the ink composition from the viewpoint that an appropriate viscosity can be easily obtained as an inkjet ink. It is preferably 20 parts by mass or more, more preferably 25 parts by mass or more, and further preferably 30 parts by mass or more. The total amount of luminescent nanocrystal particles and light-scattering particles in the ink composition is 100 parts by mass in total of the components other than the organic solvent contained in the ink composition from the viewpoint that an appropriate viscosity can be easily obtained as an inkjet ink. It is preferably 75 parts by mass or less, more preferably 65 parts by mass or less, and further preferably 55 parts by mass or less.

[Polymer dispersant]
The ink composition may further contain a polymer dispersant. The polymer dispersant is a polymer compound having a weight average molecular weight of 750 or more and having a functional group having an affinity for light-scattering particles. The polymer dispersant has a function of dispersing light-scattering particles. The polymer dispersant is adsorbed on the light-scattering particles via a functional group having an affinity for the light-scattering particles, and the light-scattering particles are generated by electrostatic repulsion and / or steric repulsion between the polymer dispersants. Disperse in the ink composition. When the ink composition contains a polymer dispersant, the light-scattering particles can be dispersed well even when the content of the light-scattering particles is relatively large (for example, when it is about 60% by mass). it can. The polymer dispersant is preferably bound to the surface of the light-scattering particles and adsorbed to the light-scattering particles, but is bound to the surface of the luminescent nanocrystal particles and adsorbed to the luminescent nanoparticles. It may be free in the ink composition.

Examples of the functional group having an affinity for the light scattering particles include an acidic functional group, a basic functional group and a nonionic functional group. The acidic functional group has a dissociative proton and may be neutralized with a base such as an amine or a hydroxide ion, and the basic functional group is neutralized with an acid such as an organic acid or an inorganic acid. You may.

The acidic functional group, a carboxyl group (-COOH), a sulfo group _(-SO 3 H), sulfuric acid group (-OSO ₃ H), a phosphonic acid group (-PO _{(OH) 3),} phosphoric acid group (-OPO ( OH) ₃ ), phosphinic acid group (-PO (OH)-), mercapto group (-SH), and the like.

Examples of the basic functional group include primary, secondary and tertiary amino groups, ammonium groups, imino groups, and nitrogen-containing heterocyclic groups such as pyridine, pyrimidine, pyrazine, imidazole, and triazole.

The nonionic functional group, hydroxy group, an ether group, a thioether group, a sulfinyl group (-SO-), a sulfonyl group _(-SO 2 -), a carbonyl group, a formyl group, an ester group, carbonic ester group, an amide group, Examples thereof include a carbamoyl group, a ureido group, a thioamide group, a thioureide group, a sulfamoyl group, a cyano group, an alkenyl group, an alkynyl group, a phosphine oxide group and a phosphine sulfide group.

The polymer dispersant may be a polymer of a single monomer (homopolymer) or a copolymer of a plurality of types of monomers (copolymer). Further, the polymer dispersant may be any of a random copolymer, a block copolymer or a graft copolymer. When the polymer dispersant is a graft copolymer, it may be a comb-shaped graft copolymer or a star-shaped graft copolymer. The polymer dispersant may be, for example, acrylic resin, polyester resin, polyurethane resin, polyamide resin, polyether, phenol resin, silicone resin, polyurea resin, amino resin, epoxy resin, polyamine such as polyethyleneimine and polyallylamine, and polyimide. It may be there.

Commercially available products can also be used as the polymer dispersant, and the commercially available products include Ajinomoto Fine-Techno Co., Ltd.'s Ajispar PB series, BYK's DISPERBYK series and BYK-series, and BASF's Efka series. Etc. can be used.

[Organic solvent]
The ink composition may further contain an organic solvent. Examples of the organic solvent include ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol dibutyl ether, diethyl adipate, dibutyl oxalate, dimethyl malonate, diethyl malonate, dimethyl succinate, and succinic acid. Examples thereof include diethyl, 1,4-butanediol diacetate, and glyceryl triacetate.

The boiling point of the organic solvent is preferably 150 ° C. or higher, more preferably 180 ° C. or higher, from the viewpoint of continuous ejection stability of the inkjet ink. Further, when forming the pixel portion, it is necessary to remove the solvent from the ink composition before curing the ink composition. Therefore, the boiling point of the organic solvent is preferably 300 ° C. or lower from the viewpoint of easy removal of the organic solvent.

The organic solvent preferably contains an acetate compound having a boiling point of 150 ° C. or higher. In this case, the affinity between the luminescent nanocrystal particles and the solvent is improved, and the luminescent nanocrystal particles can exhibit excellent luminescence characteristics. Specific examples of acetate compounds having a boiling point of 150 ° C. or higher include monoacetate compounds such as diethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate, and dipropylene glycol methyl ether acetate, and 1,4-butanediol di. Examples thereof include diacetate compounds such as acetate and propylene glycol diacetate, and triacetate compounds such as glyceryl triacetate.

In the ink composition of the present embodiment, since the photopolymerizable compound also functions as a dispersion medium, it is possible to disperse light-scattering particles and luminescent nanocrystal particles without a solvent. In this case, there is an advantage that the step of removing the solvent by drying when forming the pixel portion becomes unnecessary.

The ink composition may further contain a component other than the above-mentioned components (for example, an antioxidant such as a phosphorous acid triester compound) as long as the effect of the present invention is not impaired.

The viscosity of the ink composition described above at the ink temperature during inkjet printing may be, for example, 2 mPa · s or more, 5 mPa · s or more, or 7 mPa, from the viewpoint of ejection stability during inkjet printing. -It may be s or more. The viscosity of the ink composition at the ink temperature during inkjet printing may be 20 mPa · s or less, 15 mPa · s or less, or 12 mPa · s or less. The viscosities of the ink composition at the ink temperature during inkjet printing are, for example, 2 to 20 mPa · s, 2 to 15 mPa · s, 2 to 12 mPa · s, 5 to 20 mPa · s, 5 to 15 mPa · s, 5 to 12 mPa ·. It may be s, 7 to 20 mPa · s, 7 to 15 mPa · s, or 7 to 12 mPa · s. In the present specification, the viscosity of the ink composition is, for example, the viscosity measured by an E-type viscometer, which is measured at 25 ° C.

When the viscosity of the ink composition at the ink temperature during inkjet printing is 2 mPa · s or more, the meniscus shape of the inkjet ink at the tip of the ink ejection hole of the ejection head is stable, so that the ejection control of the inkjet ink (for example, ejection) Control of amount and discharge timing) becomes easy. On the other hand, when the viscosity of the ink composition at the ink temperature during inkjet printing is 20 mPa · s or less, the inkjet ink can be smoothly ejected from the ink ejection holes.

The surface tension of the ink composition is preferably a surface tension suitable for the inkjet method, specifically, preferably in the range of 20 to 40 mN / m, and more preferably 25 to 35 mN / m. .. By setting the surface tension within this range, discharge control (for example, control of discharge amount and discharge timing) can be facilitated, and the occurrence of flight bending can be suppressed. The flight bending means that when the ink composition is ejected from the ink ejection holes, the landing position of the ink composition deviates from the target position by 30 μm or more. When the surface tension is 40 mN / m or less, the shape of the meniscus at the tip of the ink ejection hole is stable, so that the ejection control of the ink composition (for example, control of the ejection amount and the ejection timing) becomes easy. On the other hand, when the surface tension is 20 mN / m or more, it is possible to prevent the peripheral portion of the ink ejection hole from being contaminated with the inkjet ink, so that the occurrence of flight bending can be suppressed. That is, the pixel portion forming region to be landed may not be landed accurately and the ink composition may be insufficiently filled, or the pixel portion forming region (or pixel portion) adjacent to the pixel portion forming region to be landed may be generated. The ink composition does not land on the surface and the color reproducibility does not deteriorate. The surface tension described in the specification of the present application refers to a surface tension measured at 23 ° C., which is measured by a ring method (also referred to as a ring method).

When the ink composition of the present embodiment is used as an ink composition for an inkjet method, it is preferably applied to a piezojet type inkjet recording device using a mechanical ejection mechanism using a piezoelectric element. In the piezo jet method, the ink composition is not instantaneously exposed to a high temperature during ejection. Therefore, alteration of the luminescent nanocrystal particles is unlikely to occur, and the expected luminescence characteristics can be more easily obtained in the pixel portion (light conversion layer).

Although one embodiment of the inkjet ink composition has been described above, the inkjet ink composition of the above-described embodiment can be used, for example, by a photolithography method in addition to the inkjet method. In this case, the ink composition contains an alkali-soluble resin as a binder polymer.

When the ink composition is used in a photolithography method, first, the ink composition is applied onto a substrate, and then the ink composition is dried to form a coating film. The coating film thus obtained is soluble in an alkaline developer and is patterned by being treated with an alkaline developer. At this time, since the alkaline developer is mostly an aqueous solution from the viewpoint of ease of waste liquid treatment of the developer, the coating film of the ink composition is treated with the aqueous solution. On the other hand, in the case of an ink composition using luminescent nanocrystal particles (quantum dots or the like), the luminescent nanocrystal particles are unstable with respect to water, and the luminescence (for example, fluorescence) is impaired by water. Therefore, in the present embodiment, an inkjet method that does not require treatment with an alkaline developer (aqueous solution) is preferable.

Further, even when the coating film of the ink composition is not treated with an alkaline developer, if the ink composition is alkali-soluble, the coating film of the ink composition easily absorbs moisture in the atmosphere. As time passes, the luminescence (for example, fluorescence) of luminescent nanocrystal particles (quantum dots, etc.) is impaired. From this point of view, in the present embodiment, the coating film of the ink composition is preferably alkali-insoluble. That is, the ink composition of the present embodiment is preferably an ink composition capable of forming an alkali-insoluble coating film. Such an ink composition can be obtained by using an alkali-insoluble photopolymerizable compound and a thermosetting resin as the photopolymerizable compound and the thermosetting resin. The fact that the coating film of the ink composition is alkali-insoluble means that the amount of the coating film of the ink composition dissolved in 1% by mass of a potassium hydroxide aqueous solution at 25 ° C. is based on the total mass of the coating film of the ink composition. It means that it is 30% by mass or less. The amount of the coating film of the ink composition dissolved is preferably 10% by mass or less, and more preferably 3% by mass or less. The fact that the ink composition is an ink composition capable of forming an alkali-insoluble coating film means that the thickness is obtained by applying the ink composition on a substrate and then drying it at 80 ° C. for 3 minutes. It can be confirmed by measuring the above-mentioned dissolution amount of the 1 μm coating film.

<Manufacturing method of ink composition>
The ink composition of the above-described embodiment is, for example, a component of the above-mentioned ink composition (light-emitting nanocrystal particles (for example, luminescent nanocrystal particles having an organic ligand), a photopolymerizable compound and / or thermosetting. It comprises a step of mixing a resin, a zinc compound having two ligands, and other optional components). The method for producing an ink composition may further include a step of dispersing the mixture of the above constituent components. Hereinafter, as an example, a method for producing an ink composition containing light-scattering particles will be described.

The method for producing an ink composition containing light-scattering particles includes, for example, a first step of preparing a dispersion of light-scattering particles containing light-scattering particles, a dispersion of light-scattering particles, and light emission. It comprises a second step of mixing the sex nanocrystal particles. The dispersion of the light scattering particles may further contain a polymer dispersant. In this method, the dispersion of the light scattering particles may further contain the photopolymerizable compound and / or the thermopolymerizable resin, and in the second step, the photopolymerizable compound and / or the thermopolymerizable resin is further mixed. You may. According to the above method, the light scattering particles can be sufficiently dispersed. Therefore, the optical characteristics (for example, external quantum efficiency) of the pixel portion can be improved, and an ink composition having excellent ejection stability can be easily obtained.

In the step of preparing a dispersion of light-scattering particles, the light-scattering particles, and in some cases, a polymer dispersant, a photopolymerizable compound and / or a thermopolymerizable resin are mixed and dispersed. A dispersion of light-scattering particles may be prepared. The mixing and dispersion treatment may be carried out using a dispersion device such as a bead mill, a paint conditioner, a planetary stirrer, or a jet mill. It is preferable to use a bead mill or a paint conditioner from the viewpoint that the dispersibility of the light-scattering particles is good and the average particle size of the light-scattering particles can be easily adjusted to a desired range. By mixing the light-scattering particles and the polymer dispersant before mixing the luminescent nanocrystal particles and the light-scattering particles, the light-scattering particles can be more sufficiently dispersed. Therefore, excellent ejection stability and excellent external quantum efficiency can be obtained more easily.

As a method for producing an ink composition, a dispersion of luminescent nanocrystal particles containing luminescent nanocrystal particles and a photopolymerizable compound and / or a thermopolymerizable resin is prepared before the second step. It may be further provided with a step of performing. In this case, in the second step, the dispersion of the light-scattering particles and the dispersion of the luminescent nanocrystal particles are mixed. In the step of preparing a dispersion of luminescent nanocrystal particles, the luminescent nanocrystal particles are mixed with a photopolymerizable compound and / or a thermopolymerizable resin and subjected to a dispersion treatment to disperse the luminescent nanocrystal particles. The body may be prepared. As the luminescent nanocrystal particles, luminescent nanocrystal particles having an organic ligand on the surface thereof may be used. That is, the luminescent nanocrystal particle dispersion may further contain an organic ligand. The mixing and dispersion treatment may be carried out using a dispersion device such as a bead mill, a paint conditioner, a planetary stirrer, or a jet mill. It is preferable to use a bead mill, a paint conditioner or a jet mill from the viewpoint that the dispersibility of the luminescent nanocrystal particles is improved and the average particle size of the luminescent nanocrystal particles can be easily adjusted to a desired range. According to this method, the luminescent nanocrystal particles can be sufficiently dispersed. Therefore, the optical characteristics (for example, external quantum efficiency) of the pixel portion can be improved, and an ink composition having excellent ejection stability can be easily obtained.

In this production method, the zinc compound may be blended in the first step or may be blended in the second step. That is, the first step is to disperse the light-scattering particles containing the light-scattering particles, the zinc compound, and optionally the polymer dispersant, the photopolymerizable compound and / or the thermopolymerizable resin. The body may be prepared, and the second step may be a dispersion of light-scattering particles, luminescent nanocrystal particles, a zinc compound, and in some cases, a photopolymerizable compound and / or a thermopolymerizable resin. And may be a step of mixing. The zinc compound may be contained in the dispersion of the luminescent nanocrystal particles which may be prepared before the second step.

When other components such as an antioxidant and an organic solvent are used in this production method, these components may be contained in the luminescent nanocrystal particle dispersion or in the light scattering particle dispersion. Often, the luminescent nanocrystal particle dispersion and the light scattering particle dispersion may be mixed and mixed in the obtained composition.

<Ink composition set>
The ink composition set of one embodiment includes the ink composition of the above-described embodiment. The ink composition set may include an ink composition (non-emissive ink composition) that does not contain luminescent nanocrystal particles, in addition to the ink composition (emissive ink composition) of the above-described embodiment. The non-emissive ink composition is, for example, a curable ink composition. The non-luminescent ink composition may be a conventionally known ink composition, and has the same composition as the ink composition of the above-described embodiment (luminescent ink composition) except that it does not contain luminescent nanocrystal particles. It may be.

Since the non-luminescent ink composition does not contain luminescent nanocrystal particles, light is incident on the pixel portion formed by the non-luminescent ink composition (the pixel portion containing the cured product of the non-luminescent ink composition). In this case, the light emitted from the pixel portion has substantially the same wavelength as the incident light. Therefore, the non-emissive ink composition is suitably used for forming pixel portions having the same color as the light from the light source. For example, when the light from the light source is light having a wavelength in the range of 420 to 480 nm (blue light), the pixel portion formed by the non-emissive ink composition can be a blue pixel portion.

The non-emissive ink composition preferably contains light-scattering particles. When the non-emissive ink composition contains light-scattering particles, the pixel portion formed by the non-emissive ink composition can scatter the light incident on the pixel portion, whereby the pixel It is possible to reduce the difference in light intensity of the light emitted from the unit at the viewing angle.

<Optical conversion layer and color filter>
Hereinafter, details of the light conversion layer and the color filter obtained by using the ink composition set of the above-described embodiment will be described with reference to the drawings. In the following description, the same reference numerals will be used for the same or equivalent elements, and duplicate description will be omitted.

FIG. 1 is a schematic cross-sectional view of the color filter of one embodiment. As shown in FIG. 1, the color filter 100 includes a base material 40 and a light conversion layer 30 provided on the base material 40. The light conversion layer 30 includes a plurality of pixel units 10 and a light-shielding unit 20.

The optical conversion layer 30 has a first pixel unit 10a, a second pixel unit 10b, and a third pixel unit 10c as the pixel unit 10. The first pixel portion 10a, the second pixel portion 10b, and the third pixel portion 10c are arranged in a grid pattern so as to repeat in this order. The light-shielding portion 20 is located between adjacent pixel portions, that is, between the first pixel portion 10a and the second pixel portion 10b, between the second pixel portion 10b and the third pixel portion 10c, and the third. It is provided between the pixel portion 10c of the above and the first pixel portion 10a. In other words, these adjacent pixel portions are separated from each other by the light-shielding portion 20.

The first pixel portion 10a and the second pixel portion 10b are luminescent pixel portions (light emitting pixel portions) containing a cured product of the ink composition of the above-described embodiment, respectively. The cured product shown in FIG. 1 contains luminescent nanocrystal particles, a cured component, and light scattering particles. The first pixel portion 10a includes a first curing component 13a, a first luminescent nanocrystal particle 11a and a first light scattering particle 12a dispersed in the first curing component 13a, respectively. Similarly, the second pixel portion 10b includes the second curing component 13b, the second luminescent nanocrystal particles 11b and the second light scattering particles 12b dispersed in the second curing component 13b, respectively. including. The curing component is a component obtained by the polymerization of the photopolymerizable compound and / or the curing (polymerization, cross-linking, etc.) of the thermosetting resin, and the polymer of the photopolymerizable compound and / or the cured product of the thermosetting resin. , Includes zinc atoms derived from zinc polymers. The zinc compound may exist in a state where the zinc atom and the ligand are bonded, or may exist in the state where the zinc atom and the ligand are separated. The zinc atom and the ligand may be adsorbed or coordinated (for example, bonded) to the surface of the luminescent nanocrystal particles, respectively. In addition to the above-mentioned polymer, the curing component may include an organic component (organic ligand, polymer dispersant, unreacted polymerizable compound, etc.) contained in the ink composition. In the first pixel portion 10a and the second pixel portion 10b, the first curing component 13a and the second curing component 13b may be the same or different, and may be the same as or different from the first light scattering particles 12a. It may be the same as or different from the second light scattering particle 12b.

The first luminescent nanocrystal particles 11a are red luminescent nanocrystal particles that absorb light having a wavelength in the range of 420 to 480 nm and emit light having an emission peak wavelength in the range of 605 to 665 nm. That is, the first pixel portion 10a may be rephrased as a red pixel portion for converting blue light into red light. The second luminescent nanocrystal particle 11b is a green luminescent nanocrystal particle that absorbs light having a wavelength in the range of 420 to 480 nm and emits light having an emission peak wavelength in the range of 500 to 560 nm. That is, the second pixel portion 10b may be rephrased as a green pixel portion for converting blue light into green light.

The content of the luminescent nanocrystal particles in the luminescent pixel portion is based on the total mass of the cured product of the luminescent ink composition from the viewpoint of being superior due to the effect of improving the external quantum efficiency and obtaining excellent emission intensity. It is preferably 5% by mass or more, and may be 10% by mass or more, 15% by mass or more, 20% by mass or more, or 30% by mass or more. The content of the luminescent nanocrystal particles is preferably 80% by mass or less based on the total mass of the cured product of the luminescent ink composition from the viewpoint of excellent reliability of the pixel portion and excellent luminescence intensity. It may be 75% by mass or less, 70% by mass or less, or 60% by mass or less.

The content of the light scattering particles in the luminescent pixel portion is 0.1% by mass or more and 1% by mass based on the total mass of the cured product of the luminescent ink composition from the viewpoint of being more excellent in the effect of improving the external quantum efficiency. It may be more than or equal to 3% by mass or more. The content of the light-scattering particles is 60% by mass or less, 50, based on the total mass of the cured product of the luminescent ink composition, from the viewpoint of being excellent in the effect of improving the external quantum efficiency and the reliability of the pixel portion. It may be mass% or less, 40 mass% or less, 30 mass% or less, 25 mass% or less, 20 mass% or less, or 15 mass% or less.

The third pixel portion 10c is a non-emission pixel portion (non-emission pixel portion) containing a cured product of the non-emissive ink composition described above. The cured product does not contain luminescent nanocrystal particles, but contains light-scattering particles and a cured component. That is, the third pixel portion 10c includes a third curing component 13c and a third light scattering particle 12c dispersed in the third curing component 13c. The third curing component 13c is, for example, a component obtained by polymerizing a polymerizable compound and contains a polymer of the polymerizable compound. The third light-scattering particle 12c may be the same as or different from the first light-scattering particle 12a and the second light-scattering particle 12b.

The third pixel portion 10c has a transmittance of 30% or more with respect to light having a wavelength in the range of 420 to 480 nm, for example. Therefore, the third pixel portion 10c functions as a blue pixel portion when a light source that emits light having a wavelength in the range of 420 to 480 nm is used. The transmittance of the third pixel unit 10c can be measured by a microspectroscopy.

The content of the light scattering particles in the non-emissive pixel portion is 1% by mass based on the total mass of the cured product of the non-emissive ink composition from the viewpoint that the difference in light intensity at the viewing angle can be further reduced. It may be more than 5% by mass, and may be 10% by mass or more. The content of the light-scattering particles may be 80% by mass or less, and 75% by mass or less, based on the total mass of the cured product of the non-emissive ink composition from the viewpoint of further reducing light reflection. It may be 70% by mass or less.

The thickness of the pixel portion (first pixel portion 10a, second pixel portion 10b, and third pixel portion 10c) may be, for example, 1 μm or more, 2 μm or more, or 3 μm or more. You may. The thickness of the pixel portion (first pixel portion 10a, second pixel portion 10b, and third pixel portion 10c) may be, for example, 30 μm or less, 20 μm or less, or 15 μm or less. You may.

The light-shielding portion 20 is a so-called black matrix provided for the purpose of separating adjacent pixel portions to prevent color mixing and for the purpose of preventing light leakage from a light source. The material constituting the light-shielding portion 20 is not particularly limited, and the curing of the resin composition in which the binder polymer contains light-shielding particles such as carbon fine particles, metal oxides, inorganic pigments, and organic pigments in addition to a metal such as chromium. Objects and the like can be used. The binder polymer used here includes one or a mixture of two or more resins such as polyimide resin, acrylic resin, epoxy resin, polyacrylamide, polyvinyl alcohol, gelatin, casein, and cellulose, photosensitive resin, and O / W. An emulsion-type resin composition (for example, an emulsion of a reactive silicone) or the like can be used. The thickness of the light-shielding portion 20 may be, for example, 0.5 μm or more and 10 μm or less.

The base material 40 is a transparent base material having light transmission, and is, for example, a transparent glass substrate such as quartz glass, Pyrex (registered trademark) glass, or a synthetic quartz plate, a transparent resin film, a transparent resin film for optics, or the like. A flexible base material or the like can be used. Among these, it is preferable to use a glass substrate made of non-alkali glass that does not contain an alkaline component in the glass. Specifically, "7059 glass", "1737 glass", "Eagle 200" and "Eagle XG" manufactured by Corning Inc., "AN100" manufactured by Asahi Glass Co., Ltd., "OA-10G" and "OA-10G" manufactured by Nippon Electric Glass Co., Ltd. OA-11 ”is suitable. These are materials with a small coefficient of thermal expansion and are excellent in dimensional stability and workability in high-temperature heat treatment.

The color filter 100 provided with the above optical conversion layer 30 is preferably used when a light source that emits light having a wavelength in the range of 420 to 480 nm is used.

The color filter 100 can be manufactured, for example, by forming the light-shielding portion 20 in a pattern on the base material 40 and then forming the pixel portion 10 in the pixel portion-forming region partitioned by the light-shielding portion 20 on the base material 40. .. The pixel portion 10 includes a step of selectively adhering an ink composition (inkjet ink) to a pixel portion forming region on the base material 40 by an inkjet method, a step of removing an organic solvent from the ink composition by drying, and after drying. The ink composition can be formed by a method comprising a step of irradiating the ink composition of No. 1 with active energy rays (for example, ultraviolet rays) and curing the ink composition to obtain a light emitting pixel portion. A luminescent pixel portion can be obtained by using the above-mentioned luminescent ink composition as the ink composition, and a non-luminescent pixel portion can be obtained by using the non-luminescent ink composition.

The method of forming the light-shielding portion 20 is to form a metal thin film such as chromium or a thin film of a resin composition containing light-shielding particles in a region serving as a boundary between a plurality of pixel portions on one surface side of the base material 40. However, a method of patterning this thin film and the like can be mentioned. The metal thin film can be formed by, for example, a sputtering method, a vacuum vapor deposition method, or the like, and the thin film of the resin composition containing the light-shielding particles can be formed, for example, by a method such as coating or printing. Examples of the method for patterning include a photolithography method and the like.

Examples of the inkjet method include a bubble jet (registered trademark) method using an electrothermal converter as an energy generating element, a piezojet method using a piezoelectric element, and the like.

In the drying of the ink composition, at least a part of the organic solvent may be removed, and it is preferable that all of the organic solvent is removed. The method for drying the ink composition is preferably decompression drying (decompression drying). Drying under reduced pressure is usually carried out at 20 to 30 ° C. for 3 to 30 minutes under a pressure of 1.0 to 500 Pa from the viewpoint of controlling the composition of the ink composition.

For curing the ink composition, for example, a mercury lamp, a metal halide lamp, a xenon lamp, an LED or the like may be used. The wavelength of the light to be irradiated may be, for example, 200 nm or more, and may be 440 nm or less. The exposure amount may be, for example, 10 mJ / cm ² or more, and may be 4000 mJ / cm ² or less.

Although the color filter, the optical conversion layer, and one embodiment of these manufacturing methods have been described above, the present invention is not limited to the above embodiment.

For example, the light conversion layer is a pixel portion containing a cured product of a luminescent ink composition containing blue luminescent nanocrystal particles in place of the third pixel portion 10c or in addition to the third pixel portion 10c ( A blue pixel portion) may be provided. Further, even if the light conversion layer includes a pixel portion (for example, a yellow pixel portion) containing a cured product of a luminescent ink composition containing nanocrystal particles that emit light of colors other than red, green, and blue. Good. In these cases, it is preferable that each of the luminescent nanocrystal particles contained in each pixel portion of the light conversion layer has an absorption maximum wavelength in the same wavelength range.

Further, at least a part of the pixel portion of the light conversion layer may contain a cured product of a composition containing a pigment other than the luminescent nanocrystal particles.

Further, the color filter may include an ink-repellent layer made of a material having an ink-repellent property narrower than that of the light-shielding portion on the pattern of the light-shielding portion. Further, instead of providing an ink-repellent layer, a photocatalyst-containing layer as a wettable variable layer is formed in a solid coating shape in a region including a pixel portion forming region, and then light is applied to the photocatalyst-containing layer via a photomask. Irradiation and exposure may be performed to selectively increase the ink-friendly property of the pixel portion forming region. Examples of the photocatalyst include titanium oxide and zinc oxide.

Further, the color filter may be provided with an ink receiving layer containing hydroxypropyl cellulose, polyvinyl alcohol, gelatin or the like between the base material and the pixel portion.

Further, the color filter may be provided with a protective layer on the pixel portion. This protective layer flattens the color filter and prevents the components contained in the pixel portion, or the components contained in the pixel portion and the components contained in the photocatalyst-containing layer from being eluted into the liquid crystal layer. It is provided. As the material constituting the protective layer, a material used as a known protective layer for a color filter can be used.

Further, in the manufacture of the color filter and the optical conversion layer, the pixel portion may be formed by a photolithography method instead of the inkjet method. In this case, first, the ink composition is coated on the base material in layers to form the ink composition layer. Next, the ink composition layer is exposed in a pattern and then developed using a developing solution. In this way, a pixel portion made of a cured product of the ink composition is formed. Since the developing solution is usually alkaline, an alkali-soluble material is used as the material of the ink composition. However, in terms of material usage efficiency, the inkjet method is superior to the photolithography method. This is because, in principle, the photolithography method removes about two-thirds or more of the material, and the material is wasted. Therefore, in this embodiment, it is preferable to use an inkjet ink and form a pixel portion by an inkjet method.

Further, in addition to the above-mentioned luminescent nanocrystal particles, the pixel portion of the light conversion layer of the present embodiment may further contain a pigment having substantially the same color as the luminescent color of the luminescent nanocrystal particles. In order to contain the pigment in the pixel portion, the pigment may be contained in the ink composition.

Further, one or two types of luminescent pixel portions among the red pixel portion (R), the green pixel portion (G), and the blue pixel portion (B) in the optical conversion layer of the present embodiment are luminescent nano. The pixel portion may contain a coloring material without containing crystal particles. As the color material that can be used here, a known color material can be used. For example, as the color material used for the red pixel portion (R), a diketopyrrolopyrrole pigment and / or an anionic red organic dye is used. Can be mentioned. Examples of the coloring material used for the green pixel portion (G) include at least one selected from the group consisting of a copper halide phthalocyanine pigment, a phthalocyanine-based green dye, and a mixture of a phthalocyanine-based blue dye and an azo-based yellow organic dye. Examples of the coloring material used for the blue pixel portion (B) include an ε-type copper phthalocyanine pigment and / or a cationic blue organic dye. The amount of these coloring materials used is 1 to 5 masses based on the total mass of the pixel portion (cured product of the ink composition) from the viewpoint of preventing a decrease in transmittance when contained in the light conversion layer. % Is preferable.

Hereinafter, the present invention will be specifically described with reference to Examples. However, the present invention is not limited to the following examples. All the materials used in the examples were those in which argon gas was introduced and the dissolved oxygen was replaced with argon gas. As for titanium oxide, one which was heated at 175 ° C. for 4 hours under a reduced pressure of 1 mmHg and allowed to cool in an argon gas atmosphere was used before mixing. The liquid material used in the examples was dehydrated with Molecular Sieves 3A for 48 hours or more in advance before mixing.

<Preparation of photopolymerizable compounds>
[(Meta) acrylate compound]
・ 1,4-BDDA (1,4-butanediol diacrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name: Viscoat # 195)
[N-vinyl compound]
-N-vinyl compound 1 (N-vinyl-ε-caprolactam, manufactured by BASF, trade name: NVC)
-N-Vinyl compound 2 (N-vinylpyrrolidone, manufactured by Nippon Shokubai Co., Ltd., trade name: N-vinylpyrrolidone)

<Preparation of zinc compound>
-Zinc compound 1 (bis (dibutyldithiocarbamic acid) zinc, manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd., trade name: Noxeller BZ)
-Zinc compound 2 (bis (benzothiazole-2-ylthio) zinc, manufactured by Tokyo Chemical Industry Co., Ltd.)
-Zinc compound 3 (zinc pyrithione, manufactured by Tokyo Chemical Industry Co., Ltd.)

<Preparation of green-emitting InP / ZnSeS / ZnS nanocrystal particle dispersion>
[Preparation of indium laurate solution]
10 g of 1-octadecene (ODE), 146 mg (0.5 mmol) of indium acetate and 300 mg (1.5 mmol) of lauric acid were added to the reaction flask to obtain a mixture. The mixture was heated at 140 ° C. for 2 hours under vacuum to give a clear solution (indium laurate solution). This solution was kept in the glove box at room temperature until needed. Indium laurate has low solubility at room temperature and easily precipitates. Therefore, when using an indium laurate solution, the precipitated indium laurate in the solution (ODE mixture) is heated to about 90 ° C. to become transparent. After forming the solution, the desired amount was weighed and used.

[Preparation of core (InP core) of green luminescent nanocrystal particles]
5 g of trioctylphosphine oxide (TOPO), 1.46 g (5 mmol) of indium acetate and 3.16 g (15.8 mmol) of lauric acid were added to the reaction flask to obtain a mixture. The mixture was heated at 160 ° C. for 40 minutes in a nitrogen (N ₂ ) environment and then at 250 ° C. for 20 minutes under vacuum. The reaction temperature (mixture temperature) was then raised to 300 ° C. under a nitrogen (N ₂ ) environment. At this temperature, a mixture of 3 g of 1-octadecene (ODE) and 0.25 g (1 mmol) of tris (trimethylsilyl) phosphine was rapidly introduced into the reaction flask and the reaction temperature was maintained at 260 ° C. After 5 minutes, the reaction was stopped by removing the heater and the resulting reaction solution was cooled to room temperature. Then 8 ml of toluene and 20 ml of ethanol were added to the reaction solution in the glove box. Subsequently, centrifugation was performed to precipitate InP nanocrystal particles, and then InP nanocrystal particles were obtained by tilting the supernatant. Then, the obtained InP nanocrystal particles were dispersed in hexane. As a result, a dispersion liquid (hexane dispersion liquid) containing 5% by mass of InP nanocrystal particles was obtained.

The hexane dispersion of the InP nanocrystal particles obtained above and the indium phosphide solution were placed in a reaction flask to obtain a mixture. The amount of the hexane dispersion of InP nanocrystal particles and the indium phosphide solution was adjusted to be 0.5 g (25 mg of InP nanocrystal particles) and 5 g (178 mg of indium phosphide), respectively. After allowing the mixture to stand at room temperature for 10 minutes under vacuum, the inside of the flask was returned to normal pressure with nitrogen gas, the temperature of the mixture was raised to 230 ° C., and the mixture was held at that temperature for 2 hours to remove hexane from the inside of the flask. .. The temperature inside the flask was then raised to 250 ° C., a mixture of 3 g of 1-octadecene (ODE) and 0.03 g (0.125 mmol) of tris (trimethylsilyl) phosphine was rapidly introduced into the reaction flask, and the reaction temperature was 230 ° C. Maintained in. After 5 minutes, the reaction was stopped by removing the heater and the resulting reaction solution was cooled to room temperature. Then, 8 ml of toluene and 20 ml of ethanol were added to the reaction solution in the glove box. Subsequently, centrifugation is performed to precipitate InP nanocrystal particles (InP core), which are the cores of green luminescent InP / ZnSeS / ZnS nanocrystal particles, and then by tilting the supernatant, the InP nanocrystal particles (InP core). Got Next, the obtained InP nanocrystal particles (InP core) were dispersed in hexane to obtain a dispersion liquid (hexane dispersion liquid) containing 5% by mass of the InP nanocrystal particles (InP core).

[Formation of shell (ZnSeS / ZnS shell) of green luminescent nanocrystal particles]
After adding 2.5 g of the hexane dispersion of the InP nanocrystal particles (InP core) obtained above to the reaction flask, 0.7 g of oleic acid was added to the reaction flask at room temperature, and the temperature was raised to 80 ° C. It was held for 2 hours. Next, 14 mg of diethylzinc dissolved in 1 ml of ODE, 8 mg of bis (trimethylsilyl) selenide and 7 mg of hexamethyldisirateyan (ZnSeS precursor solution) were added dropwise to this reaction mixture, and the temperature was raised to 200 ° C. and held for 10 minutes. As a result, a ZnSeS shell having a thickness of 0.5 monolayer was formed.

The temperature was then raised to 140 ° C. and held for 30 minutes. Next, a ZnS precursor solution obtained by dissolving 69 mg of diethylzinc and 66 mg of hexamethyldisiratian in 2 ml of ODE was added dropwise to this reaction mixture, and the temperature was raised to 200 ° C. and held for 30 minutes. A ZnS shell having a thickness of 2 monolayers was formed. Ten minutes after dropping the ZnS precursor solution, the reaction was stopped by removing the heater. Next, the reaction mixture was cooled to room temperature, and the obtained white precipitate was removed by centrifugation, whereby a transparent nanocrystal particle dispersion (InP / ZnSeS) in which green luminescent InP / ZnSeS / ZnS nanocrystal particles were dispersed. / ZnS nanocrystal particle ODE dispersion) was obtained.

[Synthesis of organic ligands for InP / ZnSeS / ZnS nanocrystal particles]
(Synthesis of organic ligand)
After putting polyethylene glycol | average Mn400 | (manufactured by Sigma-Aldrich) into a flask, while stirring in a nitrogen gas environment, there is an equimolar amount of polyethylene glycol | average Mn400 | and succinic anhydride (Sigma-Aldrich). Made) was added. The internal temperature of the flask was raised to 80 ° C. and stirred for 8 hours to obtain an organic ligand represented by the following formula (A) as a pale yellow viscous oil.

[Preparation of green luminescent InP / ZnSeS / ZnS nanocrystal particle dispersion by ligand exchange]
30 mg of the organic ligand was added to 1 ml of the ODE dispersion of the InP / ZnSeS / ZnS nanocrystal particles obtained above. Then, the ligand was exchanged by heating at 90 ° C. for 5 hours. As the ligand exchange progressed, agglutination of nanocrystal particles was observed. After the ligand exchange was completed, the supernatant was tilted to obtain nanocrystal particles. Next, 3 ml of ethanol was added to the obtained nanocrystal particles, and the particles were sonicated and redispersed. 10 ml of n-hexane was added to 3 mL of the ethanol dispersion of the obtained nanocrystal particles. Subsequently, centrifugation was performed to precipitate the nanocrystal particles, and then the supernatant was tilted and dried under vacuum to obtain nanocrystal particles (InP / ZnSeS / ZnS nanocrystal particles modified with the above organic ligand). The content of the organic ligand in the total amount of the nanocrystal particles modified with the organic ligand was 35% by mass. The obtained nanocrystal particles (InP / ZnSeS / ZnS nanocrystal particles modified with the above organic ligand) are dispersed in 1,4-BDDA so that the content in the dispersion is 50% by mass. A dispersion of green luminescent nanocrystal particles (QD dispersion) was obtained.

<Preparation of light-scattering particle dispersion>
In a container filled with argon gas, 33.0 g of titanium oxide (trade name: CR-60-2, manufactured by Ishihara Sangyo Co., Ltd., average particle diameter (volume average diameter): 210 nm) and a polymer dispersant (commodity) Name: Azisper PB-821, manufactured by Ajinomoto Fine Techno Co., Ltd.) was mixed with 1.0 g and 1,4-BDDA was mixed with 26.0 g, and then zirconia beads (diameter: 1.25 mm) were added to the obtained mixture. The mixture was dispersed by shaking with a paint conditioner for 2 hours, and the zirconia beads were removed with a polyester mesh filter to obtain a light scattering particle dispersion (titanium oxide content: 55% by mass).

<Example 1>
[Preparation of green ink composition (inkjet ink)]
A luminescent nanocrystalline particle dispersion, a photoscattering particle dispersion, and a photopolymerization initiator (phenyl (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (manufactured by IGM resin, trade name: Omnirad TPO)). ), 1,4-BDDA, N-vinyl compound 1, zinc compound 1, and triphenyl phosphite as an antioxidant, the contents of each component shown in Table 1 (unit: parts by mass). ), And then uniformly mixed in a container filled with argon gas, and then the mixture was filtered through a filter having a pore size of 5 μm in a glove box. Further, a filter obtained with argon gas was added. The mixture was introduced into a container, the inside of the container was saturated with argon gas, and then the pressure was reduced to remove the argon gas to obtain the inkjet ink of Example 1. The N-vinyl compound 1 of the zinc compound 1 was obtained. Solubility in was 20% by mass or more.

<Example 2>
An inkjet ink of Example 2 was obtained in the same manner as in Example 1 except that N-vinyl compound 2 was used instead of N-vinyl compound 1.

<Example 3>
An inkjet ink of Example 3 was obtained in the same manner as in Example 1 except that zinc compound 2 was used instead of zinc compound 1.

<Example 4>
An inkjet ink of Example 4 was obtained in the same manner as in Example 1 except that zinc compound 3 was used instead of zinc compound 1.

<Example 5>
Example 5 in the same manner as in Example 1 except that the N-vinyl compound was not used and the content of each component was the amount (unit: parts by mass) shown in Table 1. Obtained the inkjet ink of.

<Comparative example 1>
Ink of Comparative Example 1 in the same manner as in Example 1 except that a zinc compound was not used and the content of each component was the amount (unit: parts by mass) shown in Table 1. Got ink.

<Comparative example 2>
In the same manner as in Example 1, except that the N-vinyl compound and the zinc compound were not used, and the content of each component was the amount (unit: parts by mass) shown in Table 1. An inkjet ink of Comparative Example 2 was obtained.

<Evaluation of external quantum efficiency (EQE)>
[Preparation of sample for external quantum efficiency evaluation]
The ink composition was applied onto a glass substrate in the air with a spin coater so as to have a film thickness of 10 μm. The coating film is cured by irradiating the coating film with UV so that the integrated light amount is 1500 mJ / cm ² with a UV irradiation device using an LED lamp having a main wavelength of 395 nm in a nitrogen atmosphere, and then the cured product of the ink composition is cured on a glass substrate. Layer (photo conversion layer) was formed. As a result, a sample for evaluation was obtained.

[Measurement of EQE]
A blue LED (peak emission wavelength: 450 nm) manufactured by CCS Inc. was used as the surface emission light source. As the measuring device, an integrating sphere was connected to a radiation spectrophotometer (trade name "MCPD-9800") manufactured by Otsuka Electronics Co., Ltd., and the integrating sphere was installed above the blue LED. The prepared evaluation sample was inserted between the blue LED and the integrating sphere, and the spectrum observed by turning on the blue LED and the illuminance at each wavelength were measured.

From the spectrum and illuminance measured by the above measuring device, the external quantum efficiency was obtained as follows. The external quantum efficiency is a value indicating how much of the light (photons) incident on the optical conversion layer is emitted to the observer side as fluorescence. Therefore, if this value is large, it indicates that the light conversion layer is excellent in light emission characteristics, which is an important evaluation index.
EQE (%) = P1 (Green) / E (Blue) x 100

Here, E (Blue) and P1 (Green) represent the following, respectively.
E (Blue): represents the total value of "illuminance x wavelength / hc" in the wavelength range of 380 to 490 nm.
P1 (Green): Represents the total value of "illuminance x wavelength ÷ hc" in the wavelength range of 500 to 650 nm.
These are the values corresponding to the observed number of photons. In addition, h represents Planck's constant and c represents the speed of light.

The evaluation of the external quantum efficiency was a relative evaluation with the EQE (%) of Comparative Example 2 as 100. The results are shown in Table 2.

<Evaluation of reduction amount of wavelength shift>
A plurality of cured films having different film thicknesses were prepared using the ink composition of Comparative Example 2 so that the film thickness on the glass substrate was 12 μm, 10 μm, 8 μm, 5 μm, or 3 μm. Next, the emission spectrum of each cured film was measured in the same manner as described above, and the obtained emission peak wavelength was plotted against the film thickness. The peak wavelength of the section obtained by extrapolating the obtained approximate straight line to a film thickness of 0 μm was defined as the emission wavelength.

Next, the emission wavelength of the luminescent nanocrystal particles was compared with the wavelength of the converted light (emission light) emitted from the pixel portion, and the shift amount of the peak position (peak value of the emission light wavelength-peak value of the emission wavelength) was obtained. .. The reduction amount of the wavelength shift was evaluated based on the shift amount in Comparative Example 2. The results are shown in Table 2. As the wavelength (spectrum) of the emitted light, the spectrum measured in the above EQE evaluation was used. The emission wavelength of the luminescent nanocrystal particles was measured by the following method.

<Evaluation of light stability>
After the evaluation sample prepared by the above EQE evaluation was left to stand under the illumination lamp of the yellow room for 18 hours, the EQE was measured in the same manner as the above EQE evaluation, and the rate of change of the EQE (1- [18 hours later). EQE] / [Initial EQE] × 100) was obtained. When the rate of change was less than 5%, it was designated as A (very good), 5% or more and less than 10% was designated as B (good), and 10% or more was designated as C (bad).

10 ... Pixel part, 10a ... First pixel part, 10b ... Second pixel part, 10c ... Third pixel part, 11a ... First luminescent nanocrystal particles, 11b ... Second luminescent nanocrystal particles , 12a ... 1st light-scattering particles, 12b ... 2nd light-scattering particles, 12c ... 3rd light-scattering particles, 20 ... light-shielding part, 30 ... light conversion layer, 40 ... base material, 100 ... color filter.

Claims (17)

It contains luminescent nanocrystal particles, a photopolymerizable compound and / or a thermosetting resin, and a zinc compound having two ligands.
An ink composition in which each of the two ligands has a sulfur atom, and the sulfur atom is directly bonded to the zinc atom to coordinate with the zinc atom. The ink composition according to claim 1, wherein the zinc compound has a molecular weight of 700 or less. The ink composition according to claim 1 or 2, wherein the two ligands are compounds having a dithiocarbamic acid group as a coordinating functional group. The ink composition according to claim 3, wherein the zinc compound is a compound represented by the following formula (I).

[In formula (I), R ¹ and R ² each independently represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and a plurality of R ^1s may be the same or different from each other. , A plurality of R ^2s may be the same as or different from each other. ] The ink composition according to any one of claims 1 to 4, which contains a photopolymerizable compound. The ink composition according to any one of claims 1 to 5, wherein the photopolymerizable compound contains an N-vinyl compound. The ink composition according to claim 6, wherein the N-vinyl compound is N-vinyl-ε-caprolactam and / or N-vinylpyrrolidone. The ink composition according to claim 6 or 7, wherein the zinc compound has a solubility of 1% by mass or more with respect to the N-vinyl compound. The ink composition according to any one of claims 1 to 8, further containing light-scattering particles. The ink composition according to claim 9, further containing a polymer dispersant. The ink composition according to any one of claims 1 to 10, which is used for forming a light conversion layer. The ink composition according to any one of claims 1 to 11, which is used in an inkjet method. A method for producing an ink composition, comprising a step of mixing luminescent nanocrystal particles, a photopolymerizable compound and / or a thermosetting resin, and a zinc compound having two ligands.
A method for producing an ink composition, wherein each of the two ligands has a sulfur atom, and the sulfur atom is directly bonded to the zinc atom to coordinate with the zinc atom. A plurality of pixel portions and a light-shielding portion provided between the plurality of pixel portions are provided.
The plurality of pixel portions are light conversion layers having a light emitting pixel portion containing a cured product of the ink composition according to any one of claims 1 to 12. As the luminescent pixel portion,
A first luminescent pixel portion containing luminescent nanocrystal particles that absorb light having a wavelength in the range of 420 to 480 nm and emit light having an emission peak wavelength in the range of 605 to 665 nm.
A second luminescent pixel portion containing luminescent nanocrystal particles that absorb light having a wavelength in the range of 420 to 480 nm and emit light having an emission peak wavelength in the range of 500 to 560 nm.
The optical conversion layer according to claim 14. The light conversion layer according to claim 14 or 15, further comprising a non-light emitting pixel portion containing light scattering particles. A color filter comprising the optical conversion layer according to any one of claims 14 to 16.

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